Set myself a mission, I already have my time box, Explore, take notes and see how far I get! I know it sounds scary as a question, but also many small features can have great Exploratory coverage in a one hour session!
Ask what testing has been done already, what monitoring and tagging is in place, ask what the high risk areas are and what’s expected from the session and report. Prioritise pair-testing (with dev) the high risk areas, and areas where monitoring and tagging has been implemented.
Grab at least one of the developers who worked on it, brainstorm test charters together (time limit of max 10 minutes) and write them down. Decide on which charter to explore first and pair-explore it. 5 minutes before the end write up a summary with bugs and open charters
Assuming that I have access to a test environment with the feature installed I would use some quick tours. Start with the Feature Tour to just map out what seem to be the main features and uses of the product (this will mainly help me establish the main revenue stream of the product to help prioritise what is important). Then hop on the Claims tour to see what the product claims that it can do (as suggested we could talk to people to hear their claims about the product, but in an hour there is no time for that). Then take the Data Tour as to me this is typically the best tour for deep diving. If time allows it the next in line is Cancellation Tour (which I do not think I will get to in an hour). If possible I would like to do this together with a developer so they can observe and understand the bugs so I don’t have to spend time exploring and documenting that.
As a bonus the Variability and the Configuration tour are also good candidates depending on the product and the feature.
My main question would be “Do you have a Happy Path workflow that the majority of users will follow?” From that it would follow that those functionalities on the Happy Path are the ones I’d look at first because any bugs there would be the ones users will be most likely to encounter. They are the ones with the highest risk of reputational damage to the product.
If there was time, I’d ask the developers where they thought there was the greatest risk of bugs or other problems and look there.