SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids, 
  product_position_source.position AS position 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  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') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 1 
WHERE 
  cscart_products_categories.product_id IN (
    88313, 88312, 88311, 88310, 88261, 88260, 
    88259, 89141, 88890, 88747, 88679, 
    88678, 88336, 88392, 88206, 88205, 
    88204, 88203, 88202, 88201
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00065

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_products_categories range PRIMARY,pt pt 3 21 Using where; Using index
1 SIMPLE cscart_categories eq_ref PRIMARY,c_status,p_category_id PRIMARY 3 toolboxdigitalshop_dev.cscart_products_categories.category_id 1 Using where
1 SIMPLE product_position_source eq_ref PRIMARY,pt PRIMARY 6 const,toolboxdigitalshop_dev.cscart_products_categories.product_id 1

Result

product_id category_ids position
88201 1M 0
88202 1M 0
88203 1M 0
88204 1M 0
88205 28,1M 0
88206 1M 0
88259 1M 0
88260 1M 0
88261 1M 0
88310 1M 0
88311 1M 0
88312 1M 0
88313 1M 0
88336 1M 0
88392 1M 0
88678 1M 0
88679 1M 0
88747 1M 0
88890 1M 0
89141 1M 0