At least the couple of times that I have been to Blue Palms Brew House for Wings, Burgers and an exceptional selection of Craft Beers it has been very "Low Key Delicious" and I find Lucky Devil's down the street to be the same!
6613 Hollywood Blvd, Los Angeles, CA 90028
Blue Palms Brew House
6124 Hollywood Blvd, Los Angeles, CA
Tasca for low key small plates and good wine.
Morton's is good and low key, if you're in the mood for steakhouse. Not sure though if you mean low key, as in not pricey, not fancy, just easy or mean low key not sceney only.
I think of Lou on Vine as pretty low key, and I like the food quite a bit.
La Terza is low key but classy and not dead.
Pane e Vino's back patio is pretty low key.
If you're up for low key ethnic, try the hole in the wall Antequera Oaxaquena at Melrose & Wilton
Not sure if others agree, but even though you can people watch, I find AOC to be pretty low key as a wine bar and unlike traditional dinner service.
i second and third the recs for blue palms and lou. relaxed, comfortable, great drinks/beer/wine, and people who really care about food working for chefs who love to cook and using prime ingredients. at lou try the organic cider, and at blue palms if they still have it the black sour on draft.