As an action, insert a key into any hard, flat surface. A locked door manifests on the surface, which perfectly fits the key. Once the lock is unlocked and the door is opened, you open a portal to a pocket dimension. This dimension is a has a 60 ft by 60 ft floor, and a 10 ft high ceiling. It has a king sized bed, a plate that never runs out of bread, a cup that never runs out of water, and a bag of holding. If any of these 4 items are removed from the pocket dimension, they are immediatly permanently destroyed, and do not respawn the next time you cast the spell. Other items can be added or removed at will, allowing you to safely store your items here for an extended period of time. Any creature that is still in the pocket dimension after the 24 hours is up is magically ejected, landing wherever they previously entered. 

For every level above 3rd this spell is cast at, the pocket dimension's floor increases by an additional 30 ft by 30 ft, and the ceiling is 10 ft taller.