SELECT 
  SQL_CALC_FOUND_ROWS products.product_id, 
  IF(
    shared_descr.product_id IS NOT NULL, 
    shared_descr.product, descr1.product
  ) as product, 
  companies.company as company_name, 
  products.product_type, 
  products.parent_product_id 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'en' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN cscart_ult_product_descriptions shared_descr ON shared_descr.product_id = products.product_id 
  AND shared_descr.company_id = 1 
  AND shared_descr.lang_code = 'en' 
  LEFT JOIN cscart_product_restricted_countries AS prc ON prc.product_id = products.product_id 
  AND prc.country_code = 'US' 
WHERE 
  1 
  AND cscart_categories.category_id IN (22, 32, 33, 34, 39) 
  AND companies.status IN ('A') 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND (
    products.available_worldwide = 'Y' 
    OR prc.country_code IS NULL
  ) 
  AND !(
    products.out_of_stock_actions = 'B' && products.avail_since > 1747389739
  ) 
  AND products.parent_product_id = 0 
GROUP BY 
  products.product_id 
ORDER BY 
  products.timestamp desc, 
  products.product_id desc, 
  products.product_id ASC 
LIMIT 
  6760, 40

Query time 0.30503

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE companies ALL PRIMARY 1 Using where; Using temporary; Using filesort
1 SIMPLE cscart_categories range PRIMARY,c_status,p_category_id PRIMARY 3 5 Using where; Using join buffer (flat, BNL join)
1 SIMPLE products_categories ref PRIMARY,pt PRIMARY 3 toolboxdigitalshop_dev.cscart_categories.category_id 908 Using index
1 SIMPLE products eq_ref PRIMARY,status,idx_parent_product_id PRIMARY 3 toolboxdigitalshop_dev.products_categories.product_id 1 Using where
1 SIMPLE shared_descr eq_ref PRIMARY,product_id,company_id PRIMARY 13 toolboxdigitalshop_dev.products_categories.product_id,const,const 1 Using where
1 SIMPLE prc eq_ref PRIMARY PRIMARY 9 toolboxdigitalshop_dev.products_categories.product_id,const 1 Using where; Using index
1 SIMPLE descr1 eq_ref PRIMARY,product_id PRIMARY 9 toolboxdigitalshop_dev.products_categories.product_id,const 1 Using where
1 SIMPLE prices ref usergroup,product_id,lower_limit,usergroup_id usergroup 3 toolboxdigitalshop_dev.products_categories.product_id 1 Using where; Using index

Result

product_id product company_name product_type parent_product_id
96860 Moi (Suicide Rage Remix) Toolbox Digital Shop P 0
96859 We Don't Care Anymore (Original Mix) Toolbox Digital Shop P 0
96858 Like A Real Terror Master (Original Mix) Toolbox Digital Shop P 0
96857 Disco Fans (Original Mix) Toolbox Digital Shop P 0
96856 Coffin Lid (Original Mix) Toolbox Digital Shop P 0
96855 Life & Death (Original Mix) Toolbox Digital Shop P 0
96854 New World Order (Original Mix) Toolbox Digital Shop P 0
96853 OMG It's Alive (Original Mix) Toolbox Digital Shop P 0
96852 Like A Brick (Original Mix) Toolbox Digital Shop P 0
96851 Hardcore Gladiators (Original Mix) Toolbox Digital Shop P 0
96850 No Remorse (Original Mix) Toolbox Digital Shop P 0
96849 Bass Man (Original Mix) Toolbox Digital Shop P 0
96848 Instafuck (Original Mix) Toolbox Digital Shop P 0
96058 Bring The Noise (Original Mix) Toolbox Digital Shop P 0
96888 Ver Morta (Original Mix) Toolbox Digital Shop P 0
96045 To The Rave (Original Mix) Toolbox Digital Shop P 0
96044 Acid Train (Original Mix) Toolbox Digital Shop P 0
96042 Lets Keep On Dancing (Radio Edit) Toolbox Digital Shop P 0
96041 Lets Keep On Dancing (Extended Mix) Toolbox Digital Shop P 0
96000 Angel (Original Mix) Toolbox Digital Shop P 0
96690 Final Call (The Watchmen 180 Mix) Toolbox Digital Shop P 0
96689 Goin Down (UK Mix) Toolbox Digital Shop P 0
96688 Superhero (1989 Mix) Toolbox Digital Shop P 0
96687 The Future (Original Mix) Toolbox Digital Shop P 0
96686 A Single Time (Original Mix) Toolbox Digital Shop P 0
96685 Tell Me Now (Original Mix) Toolbox Digital Shop P 0
96684 Where's Your Head At? (Rob IYF Remix) Toolbox Digital Shop P 0
96683 Addiction Is No Good (Original Mix) Toolbox Digital Shop P 0
96682 Forever Together (Rob IYF Remix) Toolbox Digital Shop P 0
96681 We Get Down (Original Mix) Toolbox Digital Shop P 0
96680 Heaven (Original Mix) Toolbox Digital Shop P 0
96679 Til The Sunrise (Original Mix) Toolbox Digital Shop P 0
96678 Roar (The Night Time) (Original Mix) Toolbox Digital Shop P 0
96677 Get Ya Hands Up! (The Watchmen, Al Storm, Rob IYF Remix) Toolbox Digital Shop P 0
96676 Fire In Her (Dont Stop) (Original Mix) Toolbox Digital Shop P 0
96643 Inv4ders (Original Mix) Toolbox Digital Shop P 0
96640 MTC (The Watchmen, Rob IYF & Al Storm Remix) Toolbox Digital Shop P 0
96639 Toy Soldiers (Rob IYF Remix) Toolbox Digital Shop P 0
96638 Before The Fall (Original Mix) Toolbox Digital Shop P 0
96637 Good To Me (Rob IYF Remix) Toolbox Digital Shop P 0