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 = 25 
WHERE 
  cscart_products_categories.product_id IN (
    111794, 111793, 109129, 109032, 109031, 
    109011, 108892, 108891, 108790, 108632, 
    108618, 109040, 108675, 108674, 108610, 
    108901, 108900, 108884, 108883, 108554
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00068

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_products_categories range PRIMARY,pt pt 3 20 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
108554 25M 0
108610 25M 0
108618 25M 0
108632 25M 0
108674 25M 0
108675 25M 0
108790 25M 0
108883 25M 0
108884 25M 0
108891 25M 0
108892 25M 0
108900 25M 0
108901 25M 0
109011 25M 0
109031 25M 0
109032 25M 0
109040 25M 0
109129 25M 0
111793 25M 0
111794 25M 0