Accessing webinar unique join email

Our zoom webinar integration is done through marketo in order to register our users to zoom webinars. The issue is that we need to some how still through the API get access to individual registrant’s unique join code. We have the user’s email, but we do not have their zoom user ID. how with only the user’s email would we be able to get to the registrant information?

Currently the only way we can see through the API docs is that we would have to call for all registrants and then go through each page until we see one with a matching email. this seems unnecessary. Is there a way to get that single user, without having to alter the Marketo integration?