SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1016, 1341, 1342, 1390, 1347, 1339, 1338, 
    1337, 1340, 1395, 1396, 1397
  )

Query time 0.00079

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": 12,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1016,1341,1342,1390,1347,1339,1338,1337,1340,1395,1396,1397)"
    }
  }
}