Treating someone "better" does not automatically make one a racist. It can however be a form of discrimination. Only you as the individual (knows why) you are doing what you are doing.
Some people treat children better than adults, seniors better than younger folks, beautiful people better than unattractive/average looking people.
Oftentimes the person receiving the "better treatment" assumes you treat everyone the same way. They're not going to think "You're giving me the royal treatment because I'm (not) white."
To be honest no one treats (everyone) the same way!
Sometimes the mood someone is in at the time has a bearing.