If you're getting messages that apps won't run unless Google Play Services is updated and you don't have a Google account set up on your device, then you can download & install the update for your version operating system that's on your android tv box. Please note that the Google Play Services apk's uploaded here are for the android tv box version ( armeabi-v7a/nodpi ). Do not install on any other type of device or you may encounter issues. There are no Google Play Service files for 7.1.2+ Nougat. You can install the 6.0 Marshmallow version that will also cover the update for the 7.0-7.1.2 versions. Also, when trying to install the update to Google Play Services and it gives you a message - file seems to be corrupted, It could be that you already have the latest version installed on your device or you can try uninstalling the previous Google Play Services updates then try reinstalling it again. In some cases, you may need to do that for the newer version to take.
Please note that some (not all) of the newer 8.1 - 10.0 TV Boxes have the ability to update Google Services automatically or manually. Check by clicking on the Google Play Store to see if a update notification pops up.