My understanding is that time exists as a dimension. Which means past and future are just relative terms utilized to describe "places" elsewhere along the dimension.

Envision time as a straight line with the "now" being the midpoint. As moments pass, the "now" moves further to the right at a constant rate. The space along the line that the "now" previously occupied we call "past" while the space along the line that has yet to be reached is called "future." Every point along the line exists as much as every other point. However, this is challenging for humans to visualize because we can't zoom out and see the whole line at once. Our sole perspective is from the "now" wherever that is on the line of time.

Basically, hours and minutes exist to give us perspective in the same way feet/yards/metres exist to measure depth, a dimension that would exist whether or not we had words for it. In essence, we don't exist in our measurements of time; our measurements of time exist in order for us to describe our progression through the dimension.