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 (
    1139, 1134, 1140, 1141, 1147, 1148, 1149, 
    1142, 1150, 1151, 1152, 1153
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00048

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_products_categories ALL PRIMARY,pt 29 Using where; Using filesort
1 SIMPLE cscart_categories eq_ref PRIMARY,c_status,p_category_id PRIMARY 3 hobilifedt.cscart_products_categories.category_id 1 Using where

Result

product_id category_ids
1134 734M
1139 734M
1140 734M
1141 734M
1142 734M
1147 734M
1148 734M
1149 734M
1150 734M
1151 734M
1152 734M
1153 734M