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 
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') 
WHERE 
  cscart_products_categories.product_id IN (
    111756, 111755, 111754, 111753, 111752, 
    111751, 111750, 111749, 111748, 111747, 
    111746, 111745, 111744, 111743, 111742, 
    111741, 111740, 111739, 111738, 111737, 
    111736, 111735, 111734, 111733, 111732
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00040

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_products_categories range PRIMARY,pt pt 3 26 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

Result

product_id category_ids
111732 22M
111733 22M
111734 22M
111735 22M
111736 22M
111737 22M
111738 22M
111739 22M
111740 22M
111741 22M
111742 22M
111743 22M
111744 22M
111745 22M
111746 22M
111747 22M
111748 22M
111749 22M
111750 22M
111751 22M
111752 28,1M
111753 22M
111754 22M
111755 22M
111756 22M