During a webinar, is there a shortcut key (a keyboard shortcut) I can use to switch my camera and microphone on and off?

USE CASE:

The reason I'd want to do this is, as the presenter, I share my screen as soon as I go live - about 15 minutes before the scheduled start of the webianr. It shows an intro screen.

When I want to start the webinar, I move to the main slides and switch on my microphone and camera. I'd like to be able to do this without attendees seeing me flip back to the Zoho Meeting interface, then back to the presentation.