SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad946094dc6247441afe69c1798308325d8ea61550ee3dc3334037444f813b0d' 
  AND token = 'yMY73OB+v/mqnd6dZZYFdWzxAtXsoY2Y77osQ/YKFdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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