SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    10561, 10581, 10102, 9940, 10578, 10143, 
    9947, 10567, 10568, 10565, 9933, 12499, 
    12500, 10200, 10201, 10566, 10545, 
    10227, 10552, 12506
  )

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 20,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (10561,10581,10102,9940,10578,10143,9947,10567,10568,10565,9933,12499,12500,10200,10201,10566,10545,10227,10552,12506)"
    }
  }
}