You got lucky, that's for sure. The airbox is positioned to draw air from as high up in the engine bay as possible, but when you're talking about water up to the windshield, that means the engine bay was probably extremely close to water logged. Obviously, it didn't reach high enough to submerge the airbox, otherwise your engine would have shut down quite abruptly.

Typically when you dunk a car, the electronics that are not weatherproof are only a problem if the interior of the car was soaked. Most everything under the hood is waterproof thanks to the fact that pressure-washing engine bays is so popular and manufacturers don't want a reputation for cars breaking down after getting washed.

You could take the car in for service and have them look it over to make sure the CV boots aren't torn and full of rusty, nasty water now, but generally that's not going to happen to a very new car anyway. It sounds like you pretty much lucked out.