you can simply turn off the A/C but leave the fan on or at least get out of the recirculate mode) 2-3 minutes before shutting off the car, to get some fresh air and dry things out a bit before shutdown. Pick up a disinfectant that you can spray into the inside air intake in the passenger side footwell with the A/C on in recirculate mode. Spray lysol where the fresh air enters the A/C system.

Another tip:
See to it that all parts inside the car are always dry. That's why I kept all my Mercedes 240D parts such as carpets dry at all times to avoid musty smell inside the car.