I currently am not at my pc but do this:
Create two sine nodes and put time into it as usual.
Multiply one of the sines with a value < 1 ( < 0.1 should be good)
you should also multiply one of the time nodes with some value to increase/decrease the frequency.
Now take both values and Append them (it becomes a 2D Vector).
Now add your TexCoord with the Result of Append. plug that into your UVs.
€dit:
You can also try this:
Use a noise Texture and pann/rotate whatever way you want.
Now put the (red channel) noise texture into alpha of a LinearInterpolate and use A as -.02 and B as .02
Now take your Texcoord and add the result of Lerp and add plug it into your Texture UV input.