I think you could do something using Fractal Noise with the transform scales set to non-uniform (height super large and width really low) and then apply a Polar Coordinates effects, you could create a “disco ball” of light rays.
Alternatively, if you used a fractal noise with just a change to the brightness and constrast and then added CC Radial Blur, you’ll have more control over the placement.
Finally you could download the free plugin Godrays from ProductionCrate.
If you need to “mask off” specific areas, you’ll need to either precompose the noise, adding the mask in the precomp or use a circle effect before the radial blur / godrays and set to Stencil Alpha