Circuit for small level voltage detection (microvolts)
The opamp in a Sallen-Key filter is supposed to be a unity-gain buffer. Yours has a gain of +3, so it isn't surprising that it's oscillating. Wikipedia talks about this.

If you need that much gain, you need to do it elsewhere.



There's also the Application report from Texas Instruments Analysis of the Sallen Key Filter that explains why the gain of 3 or more will an issue. To be specific, Pg. No 5.