SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    302, 1013, 1045, 1019, 1032, 1044, 996, 
    1056, 1057, 1012, 1014, 1029, 1034, 
    1042, 1026, 1038
  )

Query time 0.00131

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": 16,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (302,1013,1045,1019,1032,1044,996,1056,1057,1012,1014,1029,1034,1042,1026,1038)"
    }
  }
}