SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    16346, 16348, 15749, 16347, 16338, 15753, 
    16340, 15747, 16351, 15750, 15746, 
    16337, 16336, 15745, 15734, 15741
  )

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.02861176,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 16,
          "cost": 0.02861176,
          "filtered": 100,
          "attached_condition": "cscart_products.product_id in (16346,16348,15749,16347,16338,15753,16340,15747,16351,15750,15746,16337,16336,15745,15734,15741)"
        }
      }
    ]
  }
}