SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a833f26cff0f0ff926ed15165fbd4e86f39665a5785988425963476193b44040' 
  AND token = 'KwuRr0a1/UvIvUJELGYOCl+uQhzWw7gP90lIp7jx2Ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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