Was Constable Zuvio even in The Force Awakens?
If so, when did he show up and what did he do?
The canonical Star Wars Database claims he appears in the film:
What’s an honorable Kyuzo like Constable Zuvio doing on a lawless planet like Jakku? The tough, taciturn Zuvio is the leader of Niima Outpost’s small militia, and keeps a wary yellow eye out for cheats, thieves and others bent on trouble. He is often found guarding Niima’s landing field, glowering at any local who strays too close to a visitor’s starship.
Appearances: Star Wars: Episode VII The Force Awakens
So he definitely exists in canon. He also has a canon novel (High Noon on Jakku, part of the TFA series) devoted to him, and he's also shown in the Visual Dictionary:
According to this article, he was going to have a scene in the film, but it was deleted:
The scene in which Contable Zuvio was to appear in the film would have taken place right after the thugs attack Rey in an attempt to abduct BB-8. From what I’ve heard, local peacekeeper Constable Zuvio “steps in to break up the tussle.” After settling the issue with the Constable, Rey heads back to her dwelling, “keenly aware that the dastardly Unkar would like nothing better than to get his hands on her new droid.” From what gleam, the moment with the thugs plays out differently in the film as originally Finn (FN-2187) had not yet escaped from the First Order at that point. BB-8 recognizing Finn originally happened the next day.
He also doesn't get mentioned in the official novelisation.