Yes, that is possible and while not a property itself, Mixpanel provides a method to track the time it takes for an action to occur. You can use the .timeEvent() method to mark the start of an action and then use .track() to end the timing. The duration will be automatically recorded in the “Duration” property.
For example, in React Native:
// start the timer for the event "Image Upload"
mixpanel.timeEvent("Image Upload");
// 20 seconds later...
// track "Image Upload" event
// "Duration" event property set to 20
mixpanel.track("Image Upload");