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 = 11 
WHERE 
  cscart_products_categories.product_id IN (
    710, 706, 1760, 1844, 1689, 1754, 1755, 
    1840, 1756, 1753, 1792, 1791, 1793, 
    1789, 1472, 1716, 1714, 1715, 1720, 
    1719, 1722, 1713, 1718, 1717, 1867, 
    1721, 1145, 1891, 1202, 247, 296, 1218, 
    1765, 820, 1816, 1651, 1661, 255, 65, 
    1959, 1011, 1685, 1207, 1210, 1203, 
    1389, 1188, 1190, 1209, 1186, 114, 1810, 
    113, 1742, 1598, 1565, 1597, 1708, 1694, 
    1732, 1596, 1632, 79, 297, 1852, 1456, 
    653, 1465, 1494, 1620, 1619, 1457, 1618, 
    1623, 1624, 1395, 1614, 1604, 1801, 
    1802, 1724, 1727, 1726, 1599, 1725, 
    1600, 1872, 1603, 1560, 1513, 1550, 
    1548, 1547, 1763, 1764, 1506
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00401

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": 100,
      "filtered": 100,
      "index_condition": "cscart_products_categories.product_id in (710,706,1760,1844,1689,1754,1755,1840,1756,1753,1792,1791,1793,1789,1472,1716,1714,1715,1720,1719,1722,1713,1718,1717,1867,1721,1145,1891,1202,247,296,1218,1765,820,1816,1651,1661,255,65,1959,1011,1685,1207,1210,1203,1389,1188,1190,1209,1186,114,1810,113,1742,1598,1565,1597,1708,1694,1732,1596,1632,79,297,1852,1456,653,1465,1494,1620,1619,1457,1618,1623,1624,1395,1614,1604,1801,1802,1724,1727,1726,1599,1725,1600,1872,1603,1560,1513,1550,1548,1547,1763,1764,1506)"
    },
    "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
    }
  }
}