Sweep Timeout?

I recently removed the BruteProtect plugin – it has left the wp_options table with transient count as follows:

There are a total of 70,657 Options.

When I run the sweep, it runs for a short while and then stops (ie. the count stops going down if I look at it in phpMyAdmin).

However, the plugin status remains as ‘sweeping’.

Is there a timeout? If so, how can I clear this enormous amount of transients?

https://www.ads-software.com/plugins/wp-sweep/