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 (
    1612, 1267, 1400, 1652, 1309, 1673, 1653, 
    1668, 1634, 1688, 1499, 1613, 1648, 
    1723, 1590, 1510, 1950, 1951, 1924, 
    1949, 1745, 1654, 1501, 69, 89, 1643, 
    1645, 1925, 1666, 1664, 1557, 1695, 
    1559, 1315, 1310, 1471, 1502, 86, 1504, 
    33, 1944, 1942, 1900, 1433, 1777, 1748, 
    1679, 1702
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00182

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": 49,
      "filtered": 100,
      "index_condition": "cscart_products_categories.product_id in (1612,1267,1400,1652,1309,1673,1653,1668,1634,1688,1499,1613,1648,1723,1590,1510,1950,1951,1924,1949,1745,1654,1501,69,89,1643,1645,1925,1666,1664,1557,1695,1559,1315,1310,1471,1502,86,1504,33,1944,1942,1900,1433,1777,1748,1679,1702)"
    },
    "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
    }
  }
}