door with key that automatically closes?

[milk]

i want to make a door with a chest on the floor to enter a key, opening the door, then closing it after around 3-5 seconds
i used this thread as a base:
https://hypixel.net/threads/guide-housing-redstone-shops.4155546/
i made it work but it either takes too many keys from the bottom hopper or has it open infinitely
any ways to build this?

free plugins
minecraft paid for free
SpigotMC
minecraft plugins
mcmarket
mc-market
spigotmc
free minecraft paid plugins
free minecraft plugins
aac free
ewg free
Minecraft Premium Plugins
ewg free download
litebans free
epicworldgenerator free
free schematics
leaked schematics minecraft
schematics
schematics leaked
schematics free
minecraft schematics free
paid minecraft schematics free
paid minecraft schematics for free
free cracked plugins
free cracked minecraft plugins
plugins
featherboard download
featherboard plugin download
antiaura download
xenforo leaked
xenforo for free
xenforo addons