SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd36a1f9a37c03b8eabe0452ff1679690cd7e92b292016a7f618c19874aaa9996' 
  AND token = 'KNvmcqdA5N2j7OKGJkdoAjO2ITuqgp4Xvdhd1udfrZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}