SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    10494, 10492, 10468, 9903, 10487, 9899, 
    10473, 10486, 9881, 9896, 9892, 10481, 
    9876, 10474, 10491, 10489, 10471, 9880, 
    10472, 9885
  )

Query time 0.00156

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 (10494,10492,10468,9903,10487,9899,10473,10486,9881,9896,9892,10481,9876,10474,10491,10489,10471,9880,10472,9885)"
    }
  }
}