SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11d4bf958e94ca05144d669e75eb306d217c53b8ea4c3a62293a4d8e0dc58749' 
  AND token = 'iug4JAXgYw9Bg7RLKOw/hTzMFXvblGmz/MEYOwxoy20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}