Warehouse Keeper Mia:
Hmm...this key doesn't fit.
Do you have any more pieces of the key or another Records Chest?
If you don't, please go to the Field of Silence and get rid of the Tasaba Lizardmen and Tasaba Lizardman Shaman there. Once you have done so, you will be able to obtain both the pieces of the key to the Records Chest and the Records Chest itself.