I think you’ll have to set the authentication to “None or self handled” and then make a header for your authorization key and value. You’ll have to make that key not private, and then you can fill in the key dynamically. Just make sure you set your privacy rules so you don’t reveal the API key.
Disclaimer: I’m still new to this, and I still have some security concerns with this method since I think the API key would be handled on the browser level. Maybe someone with more experience can weigh in.