TIGERRB98'S PROFILE

If you want a locked chest use conditional branch (found on the first page of event commands), go to the 4th page of conditional branch, choose item and select which item you need in your inventory in order to open the chest and click OK.
Now you should put a message bellow " : Else " to show the player that the chest is locked and above " : Else " you can put the same events as in this tutorial.

P.S.
In the database you can make a new item in the items tab by changing the maximum number of items with change maximum at the bottom left corner.
You can name the item, put a description for the item that appears to the player if his cursor hovers over the item and you can you can choose an icon for the item. Just remember to leave price at zero, change consumable to no and occasion to never so the player doesn't accidentally sell or use the item.