SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    10310, 10311, 10312, 12999, 13000, 13001, 
    13002, 13003, 13004, 13005, 13006, 
    13007, 13008, 13009, 13010, 13011, 
    13012, 9874, 9875, 9887
  )

Query time 0.00140

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 (10310,10311,10312,12999,13000,13001,13002,13003,13004,13005,13006,13007,13008,13009,13010,13011,13012,9874,9875,9887)"
    }
  }
}