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 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 (
    (
      1 
      AND products.product_id IN (
        103835, 103836, 103837, 103838, 103839, 
        103840, 103841, 103842, 103843, 103844, 
        103845, 103846, 103847, 103848, 103849, 
        103850, 103851, 103852, 103853, 103854, 
        103855, 103856, 103857, 103858, 103859, 
        103860, 103861, 103862, 103863
      )
    ) 
    AND companies.status IN ('A') 
    AND prices.usergroup_id IN (0, 0, 1)
  ) 
  AND (
    products.available_worldwide = 'Y' 
    OR prc.country_code IS NULL
  ) 
GROUP BY 
  products.product_id 
ORDER BY 
  products.timestamp desc, 
  products.product_id desc, 
  products.product_id ASC

Query time 0.00181

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 products range PRIMARY,status PRIMARY 3 29 Using where; Using join buffer (flat, BNL join)
1 SIMPLE shared_descr eq_ref PRIMARY,product_id,company_id PRIMARY 13 toolboxdigitalshop_dev.products.product_id,const,const 1 Using where
1 SIMPLE prc eq_ref PRIMARY PRIMARY 9 toolboxdigitalshop_dev.products.product_id,const 1 Using where; Using index
1 SIMPLE prices ref usergroup,product_id,lower_limit,usergroup_id usergroup 3 toolboxdigitalshop_dev.products.product_id 1 Using where; Using index
1 SIMPLE descr1 eq_ref PRIMARY,product_id PRIMARY 9 toolboxdigitalshop_dev.products.product_id,const 1 Using where
1 SIMPLE products_categories ref PRIMARY,pt pt 3 toolboxdigitalshop_dev.products.product_id 1 Using index
1 SIMPLE cscart_categories eq_ref PRIMARY,c_status,p_category_id PRIMARY 3 toolboxdigitalshop_dev.products_categories.category_id 1 Using where

Result

product_id product company_name product_type parent_product_id
103863 Differences (Original Mix) Toolbox Digital Shop P 0
103862 I Don't Care (Original Mix) Toolbox Digital Shop P 0
103861 Are You All Ready? (Original Mix) Toolbox Digital Shop P 0
103860 In It For Kicks (Original Mix) Toolbox Digital Shop P 0
103859 Hellraiser (Original Mix) Toolbox Digital Shop P 0
103858 The Dawn (Paul Janes Remix) Toolbox Digital Shop P 0
103857 Man On The Moon (Original Mix) Toolbox Digital Shop P 0
103856 Music Is The Drug (Original Mix) Toolbox Digital Shop P 0
103855 Serious Sound (Original Mix) Toolbox Digital Shop P 0
103854 Til Tears Do Us Part (Stimulant DJs Remix) Toolbox Digital Shop P 0
103853 Blueprint (Tara's Theme) (Original Mix) Toolbox Digital Shop P 0
103852 Critical Mass (Original Mix) Toolbox Digital Shop P 0
103851 Slammin (Flash Harry Remix) Toolbox Digital Shop P 0
103850 Turntablism (Original Mix) Toolbox Digital Shop P 0
103849 9 Bar (Dark by Design Remix) Toolbox Digital Shop P 0
103848 Take Off (Original Mix) Toolbox Digital Shop P 0
103847 What Can You Do 4 Me? (Tidy Boys Remix) Toolbox Digital Shop P 0
103846 Good Side (Andy Farley Remix) Toolbox Digital Shop P 0
103845 Stronger (Original Mix) Toolbox Digital Shop P 0
103844 Hybridize (Original Mix) Toolbox Digital Shop P 0
103843 Ready 4 Dis (Original Mix) Toolbox Digital Shop P 0
103842 Only Me (Stimulant DJs Remix) Toolbox Digital Shop P 0
103841 Be Alive (Original Mix) Toolbox Digital Shop P 0
103840 Higher (Original Mix) Toolbox Digital Shop P 0
103839 In Control (Colin Barratt Remix) Toolbox Digital Shop P 0
103838 Wizards Of The Sonic (Original Mix) Toolbox Digital Shop P 0
103837 Emotion (Original Mix) Toolbox Digital Shop P 0
103836 I Want It (Original Mix) Toolbox Digital Shop P 0
103835 Nightmare Man (Original Mix) Toolbox Digital Shop P 0