SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    19408, 19618, 8216, 7549, 18424, 7562, 
    18828, 7188, 19726, 18580, 8759, 8197, 
    12511, 8408, 8234, 6672
  )

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "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 (19408,19618,8216,7549,18424,7562,18828,7188,19726,18580,8759,8197,12511,8408,8234,6672)"
        }
      }
    ]
  }
}