Curing in airtight container

I need to cure large molds indoors. Mold is around 13″x24″x1″. I’d like to store it in something like an airtight plastic container – like those for underbed storage. I see containers that are ‘weatherproof’ but can’t find any that are airtight. I guess I could just caulk my own silicon sealant around the lid once closed, but that’s a pain. Any recommendations for an inexpensive curing box to safely cure large rectangular molds indoors?