SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '887969e9e824846e4142e269eda58a61256afe5b91bff3605b9da93f04dcfbab' 
  AND token = 'wtzy7aGVvyHIFSXUKF+YhXC0vDwgcsMp4ZFLIiIhCZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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