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.company_id = 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 = 2359 
WHERE 
  cscart_products_categories.product_id IN (
    3900, 3901, 3913, 116, 3909, 3910, 3911, 
    120, 118, 3914, 3912, 3897, 53, 5881, 
    3898, 3899
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00213

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": 274,
      "filtered": 100,
      "index_condition": "cscart_products_categories.product_id in (3900,3901,3913,116,3909,3910,3911,120,118,3914,3912,3897,53,5881,3898,3899)"
    },
    "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", "rfswire_cart.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": ["rfswire_cart.cscart_products_categories.category_id"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "cscart_categories.company_id = 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')"
    }
  }
}

Result

product_id category_ids position
53 1047,144,1052,147,2314,2359,2393,2366,1046,2367,139,142M 0
116 147,142,1052,143,141,146,144,145,140,2314,2366,1046,2359,139,2367,1053,1047,1051,1054,218,217M 0
118 147,143,144,140,146,139,142,2314,2359,2366,141,2367,218,217M 0
120 146,147,141,217,145,144,143,139,140,2359,2366,2314,2367,218,142M 0
3897 2393,2367,2366,2359,2314,1052,1047,1046,147,144,142,139M 80
3898 2393,2359M 0
3899 2393,2359M 0
3900 2393,2367,2366,2359,2314,1054,1053,1052,1051,1047,1046,218,217,216,147,146,145,144,143,142,141,140,139M 190
3901 2367,2366,2359,2314,1054,1053,1052,1051,1047,1046,218,217,147,146,145,144,143,142,141,140,139M 180
3909 2367,2366,2359,2314,1054,1053,1052,1051,1047,1046,218,217,216,147,146,145,144,143,142,141,140,139M 190
3910 2367,2366,2359,2314,1054,1053,1052,1051,1047,1046,218,217,147,146,145,144,143,142,141,140,139M 180
3911 2367,2366,2359,2314,1054,1053,1052,1051,1047,1046,218,217,147,146,145,144,143,142,141,140,139M 180
3912 2367,2366,2359,2314,218,217,147,146,144,143,142,141,140,139M 110
3913 2367,2366,2359,2314,1054,1053,1052,1051,1047,1046,218,217,216,147,146,145,144,143,142,141,140,139M 190
3914 2367,2366,2359,2314,218,217,147,146,145,144,143,142,141,140,139M 120
5881 144,143,142,141,140,145,146,147,216,217,218,1046,1047,1051,1052,1053,1054,2314,2359,2366,2367,139M 190