Yes, you can typically still find some places to eat at “regular” dinner times, but they will be fairly empty (aside from those catering specifically to tourists).
However, some restaurants do modify their opening times and won’t open until later (8 or 9 pm). So if you have your heart set on a spot, it’s best to check ahead of time. And if you want to see how the city really lives, wait a couple more hours – snack on some Jamón and wine while you’re waiting!