This got two early unclear votes but was ultimately closed as opinion-based. I think people are getting hung up on the OP wondering how to define "quick" which I don't think is the main point of the question. It's part of what's adding to his confusion in how to handle this type of question but the main question is ultimately "How should I respond?" and it's broader than "please define what 'quick' means at work". I've edited the question somewhat to focus on the main question and I think this is on-topic here and answerable. None of the three answers currently posted are focusing on the exact definition of quick but rather on how you respond to a request like this.
Disclaimer: I've answered this question.