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 = 1850 
WHERE 
  cscart_products_categories.product_id IN (
    65070, 65008, 65044, 65052, 65123, 65065, 
    65060, 65000, 65056, 65525, 65655, 
    65656, 65658, 65810, 65820, 65806, 
    65800, 65817, 65659, 65657, 65789, 
    65895, 65937, 65888
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00102

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": 137,
      "filtered": 100,
      "attached_condition": "cscart_products_categories.product_id in (65070,65008,65044,65052,65123,65065,65060,65000,65056,65525,65655,65656,65658,65810,65820,65806,65800,65817,65659,65657,65789,65895,65937,65888)",
      "using_index": true
    },
    "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", "cscart_migrate.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": ["cscart_migrate.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
65000 1594,1850,1928M 0
65008 1594,1644,1850,1928M 0
65044 1594,1850,1928M 0
65052 1594,1850,1928M 0
65056 1594,1850,1928M 0
65060 1594,1850,1928M 0
65065 1594,1850,1928M 0
65070 1594,1850,1928M 0
65123 1588,1616,1653,1804,1850,1926,2002,1928M 0
65525 1594,1846,1850,1928,1924M 0
65655 1765,1844,1850,1922,1928,1983,2002,1985M 0
65656 1542,1844,1850,1922,1928,1983,2002,1985M 0
65657 1844,1850,1922,1928,1983,2002,1985M 0
65658 1844,1850,1922,1928,1983,1985,2002,1743M 0
65659 1844,1850,1922,1928,1983,2002,1985M 0
65789 1850,1924,1928,2002,1846M 0
65800 1846,1850,1922,1924,1928,2002,1844M 0
65806 1846,1850,1922,1924,1928,2002,1844M 0
65810 1846,1850,1922,1924,1928,2002,1844M 0
65817 1621,1846,1850,1922,1924,1928,2002,1844M 0
65820 1621,1846,1850,1922,1924,1928,2002,1844M 0
65888 1844,1922,1928,1850M 0
65895 1846,1850,1922,1924,1928,2002,1844M 0
65937 1844,1922,1928,1983,1985,1850M 0