It's been kinda the meme of the week, that Chasity belts in fact probably never existed, and if they did were more for novelty use and whipped up for museums.
I console myself with the thought that "Fury Road" is set in the future.
That said, the more literal and kinky members of society have been quick to embrace them, and six centuries later there's any number of suppliers to be found online. I'll let you do your own research there...
There were, however, any number of ideas for anti-erection and anti-mastubatory devices patented. I'd be curious to see the resultant psychology of any child that suffered an adolescence wearing one of these:
More at (appropriately enough) Christwire. I'm not making this up, they even added their website to the image - clearly any self-respecting anti-mastubator or erectionist would want a Jesus branded and approved product, although I have to say I think I have a very different understanding of both arousing and the Bible than they do.
And, finally, proof that the more things change, the more they stay the same - anti-erection boxers, to save your child from the embarrassment of a poorly timed boner.
It's a wonderful world.