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 = 265 
WHERE 
  cscart_products_categories.product_id IN (
    10177, 10175, 9813, 10095, 9904, 10178, 
    10644, 10093, 10096, 10167, 10525, 
    10526, 10527, 10528, 10529, 10530, 
    10531, 10532, 10533, 10534, 10535, 
    10536, 10537, 10538, 10539, 10540, 
    10541, 10542, 10524, 10543, 10544, 
    13013, 13014, 13015, 13016, 13017, 
    13018, 13019, 13020, 13021, 13022, 
    13023, 13024, 13025, 13026, 13027, 
    13028, 13029, 13030, 10688, 10727, 
    10728, 10729, 10730, 10731, 10732, 
    10733, 10313, 10314, 10315, 10316, 
    10317, 10318, 10319
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00325

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": 64,
      "filtered": 100,
      "index_condition": "cscart_products_categories.product_id in (10177,10175,9813,10095,9904,10178,10644,10093,10096,10167,10525,10526,10527,10528,10529,10530,10531,10532,10533,10534,10535,10536,10537,10538,10539,10540,10541,10542,10524,10543,10544,13013,13014,13015,13016,13017,13018,13019,13020,13021,13022,13023,13024,13025,13026,13027,13028,13029,13030,10688,10727,10728,10729,10730,10731,10732,10733,10313,10314,10315,10316,10317,10318,10319)"
    },
    "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')"
    }
  }
}