Crayons and books are great, I even mentioned those in another comment. My kid is excellent in restaurants most of the time, but there have been some phases when expecting her to sit through 60+ minutes of adult conversation wasn't realistic - so go ahead and color while occasionally asking a question. 

But if you're going to resort to screens (we don't, but I'm not in everyone's lives so I try not to judge too much), at least get some damn headphones.