There's an indirect way to set an Alert based on multiple columns of a query: 

Your query can implement the alert logic and return a boolean value for the Alert to trigger on. Something like:

SELECT CASE WHEN drafts_count > 10000 AND archived_count > 5000 THEN 1 ELSE 0 END FROM ( SELECT sum(CASE WHEN is_archived THEN 1 ELSE 0 END) AS archived_count, sum(CASE WHEN is_draft THEN 1 ELSE 0 END) AS drafts_count FROM queries) data 

This query will return 1 when drafts_count > 10000 and archived_count > 5000. Then you can configure the alert to trigger when the value is 1.