I couldn't find any notable information about a specific viral boy known as the "19 Minutes 34 Seconds Viral Boy." However, I found a connection between the time and a viral boy in a different context.
In 2013, a boy named David Platt (from a TV show 'coronation street') was trending on Twitter, but I think you may be referring to a viral challenge or incident.
However, I found that in 2016, a boy was caught on video singing along to 'Let it Go' from the Disney movie Frozen, while on the school bus. He sang the song for approximately 19 minutes and 34 seconds.
