A Dress That Can Be Locked

I’m looking for some suggestions! I have a sissy dress with a lock, and my goal is to stay locked inside it for roughly twenty-four hours. The challenge is ensuring I can’t unlock myself during that period. My initial thought was to secure the dressing before going to sleep, placing the key at the far end of the garden. This way, I’d spend the night in the dress and wouldn’t be able to get out until darkness falls again the next evening when it’s feasible to walk down there. So far, that seems like the only method where escape is truly prevented. Do you have any other ideas?