I have lots of experience working with Discord API and use Discord for personal use daily, and can definitely make this license management bot for you to your liking within any deadline you give me.
If you are interested in knowing how I would create the project, I would use it would be NodeJS (DiscordJS Node Module for the bot) and MongoDB for the database (for saving the keys!).
The bot could easily be hosted on any virtual machine or your personal computer (if you never shut down your computer that is), and of course I would help you set it up.
Hope to hear from you