My 2012 Honda is a brick

My 2012 Honda has been driving fine. Forever. I've never had a problem with it. But last night I went to Chipotle, parked my car, and came back out after 5ish minutes. When I put the key in the ignition… Nothing. No clicks, no lights, no electric locks or windows. The brakes also won't depress. So I'm assuming it's either the main relay or ignition switch? I'm borrowing a power probe tonight to try to get a little more information. Any other thoughts?

Battery flat or in some way disconnected from the car
it is 100% normal for the brake pedal to be harder to depress when the engine is not running