Alright, first of all, open your Android SDK Manager: Tools -> Android -> SDK Manager, then chose any platform/package you want to download, expand it and select ARM EABI v7a System Image
or ARM 64 v8a System Image
then install.
After that, open Android AVD Manager: Tools -> Android -> AVD Manager and create an emulator. You may chose from existing or create your own.
For better results, you may need to restart Android Studio.
[UPDATE]
Thanks to @bjornredemption for his clue.
As per Google's latest documentation for Android Emulator v29+ Navigate to Tools -> Android -> SDK Manager then select the "SDK Tools" tab and tick this option:
Android Emulator Hypervisor Driver for AMD Processors
Then click Apply to download then use it for your emulator.