Add in Virtualmin → Scheduled Cron Jobs, every minute:
wget -q -O /dev/null "https://demo.cloudwizard.eu/CW/MailEngine/cron.php?key=********" >/dev/null 2>&1
php /home/cloudwizard/domains/demo.cloudwizard.eu/public_html/CW/MailEngine/cron.php >/dev/null 2>&1
Self-limits to 50s per run — won't overlap.