SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91df31c689f82820f7f6527883627a00f73e59b08d80e723de6747b0bef085a3' 
  AND token = 'Kf05X4qgzPZ3OYHDxWWoi7q++fwhD0Kx4hIwDJ/ITsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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