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 = 439 
WHERE 
  cscart_products_categories.product_id IN (
    10744, 10745, 10746, 10688, 10727, 10728, 
    10729, 10730, 10731, 10732, 10733, 
    10313, 10314, 10315, 10316, 10317, 
    10318, 10319, 10320, 10321, 10322, 
    10459, 10460, 10461, 10462, 10463, 
    10464, 10465, 10829, 10830, 10831, 
    10832, 10833, 10834, 10835, 10836, 
    10837, 10838, 10839, 10596, 10597, 
    10598, 10599, 10600, 10521, 10520, 
    10519, 10518, 10517, 10516, 10515, 
    10514, 10513, 10512, 10511, 10510, 
    10509, 10508, 10507, 10506, 10505, 
    10504, 10503, 10502, 10501, 10500, 
    10499, 10498, 10497
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00488

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products_categories",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "pt"],
      "key": "pt",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 69,
      "filtered": 100,
      "index_condition": "cscart_products_categories.product_id in (10744,10745,10746,10688,10727,10728,10729,10730,10731,10732,10733,10313,10314,10315,10316,10317,10318,10319,10320,10321,10322,10459,10460,10461,10462,10463,10464,10465,10829,10830,10831,10832,10833,10834,10835,10836,10837,10838,10839,10596,10597,10598,10599,10600,10521,10520,10519,10518,10517,10516,10515,10514,10513,10512,10511,10510,10509,10508,10507,10506,10505,10504,10503,10502,10501,10500,10499,10498,10497)"
    },
    "table": {
      "table_name": "product_position_source",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY", "pt"],
      "key": "PRIMARY",
      "key_length": "6",
      "used_key_parts": ["category_id", "product_id"],
      "ref": [
        "const",
        "noframes_angrybeaver.cscart_products_categories.product_id"
      ],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["category_id"],
      "ref": ["noframes_angrybeaver.cscart_products_categories.category_id"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "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')"
    }
  }
}