SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4f875cc6ae8597c322997b36951d5c48ae6fab7edba0bf034a82bf6090ada6b' 
  AND token = 'O0+SY3F4VJ7FDuo7nYgNh+AOKubxiEJBKXjEGAbGvWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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