SELECT 
  tmall_products.* 
FROM 
  tmall_products 
WHERE 
  tmall_products.product_id IN (
    168, 167, 169, 161, 165, 166, 163, 164
  )

Query time 0.00833

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.01458715,
    "nested_loop": [
      {
        "table": {
          "table_name": "tmall_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 8,
          "cost": 0.01458715,
          "filtered": 100,
          "index_condition": "tmall_products.product_id in (168,167,169,161,165,166,163,164)"
        }
      }
    ]
  }
}