Your only option is insurance. You're not gonna find an all-steel pair (would be terribly uncomfortable) with somehow unscratchable lenses, and short of that, how could any pair be bifl.
Honestly, if they have flexible or generally solid hinges, that's the most you can do to avoid the most common point of failure in cheap glasses, and beyond that, their longevity depends on use much more than build quality.
As for sustainability, there are a lot of cheap and nice brands using recycled materials or bamboo. But the best thing you can do is treat a pair well so you can go longer before replacing them.