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 = 7 
WHERE 
  cscart_products_categories.product_id IN (
    1431, 360, 1479, 1478, 414, 1866, 1427, 
    788, 1084, 1407, 1903, 1452, 1453, 538, 
    1864, 1863, 1461, 1199, 1943, 1901, 
    1200, 1212, 1939, 1211, 759, 1415, 1255, 
    1796, 23, 24, 1468, 1466, 1467, 1482, 
    1484, 1568, 1535, 1566, 1567, 1444, 
    1418, 1443, 1054, 1369, 1370, 60, 808, 
    1274, 1030, 1437, 1780, 1031, 807, 1487, 
    806, 1032, 1033, 1470, 370, 1573, 1752, 
    1424, 1423, 1744, 934, 1010, 1434, 1818, 
    153, 1290, 1291, 1292, 1917, 1916, 505, 
    395, 1795, 215, 214, 217, 212, 216, 234, 
    213, 1491, 1496, 1497, 1498, 1480, 1570, 
    1571, 1572, 1626, 1784, 1286, 1287
  ) 
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": 97,
      "filtered": 100,
      "index_condition": "cscart_products_categories.product_id in (1431,360,1479,1478,414,1866,1427,788,1084,1407,1903,1452,1453,538,1864,1863,1461,1199,1943,1901,1200,1212,1939,1211,759,1415,1255,1796,23,24,1468,1466,1467,1482,1484,1568,1535,1566,1567,1444,1418,1443,1054,1369,1370,60,808,1274,1030,1437,1780,1031,807,1487,806,1032,1033,1470,370,1573,1752,1424,1423,1744,934,1010,1434,1818,153,1290,1291,1292,1917,1916,505,395,1795,215,214,217,212,216,234,213,1491,1496,1497,1498,1480,1570,1571,1572,1626,1784,1286,1287)"
    },
    "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": ["bacpvdev_db.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')"
    },
    "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", "bacpvdev_db.cscart_products_categories.product_id"],
      "rows": 1,
      "filtered": 100
    }
  }
}