Your admin can set up rules that allow you to book a meeting with the related Account / Contact / Lead / Opportunity / Case owner directly based on specific rules.
If an ownership queue like that is set up with ownership rules, when you book a meeting with a prospect in Instant Booker the owner will be highlighted as "Matched to".
If you think the owner is not correctly marked on this type of calendar, you can change the owner from the left navigation directly unless your admin has also set the queue to strict mode, meaning the assignee can't be changed.