The part where it says:
The prince had provided all the appliances of pleasure. There were buffoons, there were improvisatori, there were ballet-dancers, there were musicians, there was Beauty, there was wine. All these and security were within. Without was the "Red Death."
is the best demonstrative of what could be a foreshadowing for what will happen. Look at how the name Prospero "one who has prospered" has allotted provisions for people to entertain, protect, feed, and make them feel secure. However, within this description you can appreciate a form of morbid optimism, as everything is laid out as to oust any possibility of a mishappening- which is never the case even in the best laid plans. Such prosperity and superiority hardly come to any human being without a price. Prospero will eventually pay his.