I can confirm that it is Avast firewall.
Regarding the scanning, what type of scan are you running?
Remember a full scan will take long since it populates the cache. I'd recommend "unchecking" follow links during scan and "check" scan files in order in both quick and full scans.
With a resident AV such as Avast, you don't need to scan much. A weekly/monthly quick scan would suffice alongside a Malwarebytes scan.