SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f390b42fe3ad5b09952df3bcdb4e87ed113f36a5f7fb0f8293801cce1042b7d8' 
  AND token = 'QDLYsocnlfycSeNnTVbFrmBYmH8AzU3hDMYV2rWyAQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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