How do I add concurrency limits to a scheduled query in BigQuery

1. I monitor my logs for an externally controlled event.
2. The observation of an instance of that externally controlled event triggers a Cloud Function (I intentionally limit the maximum instances of the Cloud Function to 1).

3. The Cloud Function triggers an “on-demand” Scheduled Query in BigQuery.

First Preference:

Can I set a limit to the number of active instances of a BigQuery on-demand Scheduled Query to just one (kind of like how I limit the instances of the Cloud Function to just one at a time)?

Alternative Possibility:

(If I cannot limit the number of instances directly) Can I limit the the BigQuery on-demand Scheduled Query to not run if it has been triggered less than five minutes ago?