SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    12672, 12671, 12994, 12993, 12992, 12991, 
    12990, 12989, 12988, 12987, 12986, 
    12985, 10343, 10345, 10346, 10347, 
    10348, 10349, 10323, 10350
  )

Query time 0.00047

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 (12672,12671,12994,12993,12992,12991,12990,12989,12988,12987,12986,12985,10343,10345,10346,10347,10348,10349,10323,10350)"
    }
  }
}