How to stop cron process without rebooting my server?

I have tried the following:

drush php-eval "\Drupal::lock()->release('cron');"

This had no effect. I'm still seeing "Attempting to re-run cron" errors pile up in the log.

I also tried the mysql query:

DELETE FROM semaphore WHERE name = 'cron';

The query ran fine, but had no effect. I'm still seeing "Attempting to re-run cron" errors pile up in the log.

I also checked the processes:

ps aux | grep cron

I saw a number of Drupal-related cron processes, and killed them all.

I then repeated...

drush php-eval "\Drupal::lock()->release('cron');"

None of this has had any effect. I clear the log, and then new "Attempting to re-run cron" errors appear.