Specifically:
A hard real-time operating system has less jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS that can usually or generally meet a deadline is a soft real-time OS, but if it can meet a deadline deterministically it is a hard real-time OS.
Async, non-blocking, and event-driven have nothing to do with real-time.
This web framework has nothing to do with real-time.
Stop using terminology you don't understand.
As posted in http://en.wikipedia.org/wiki/Real-time_web
"The real-time web is a set of technologies and practices that enable users to receive information as soon as it is published by its authors, rather than requiring that they or their software check a source periodically for updates."
Mojolicious fits that description.