Unfortunately, Excel is a poor choice here as it assumes you want the whole csv file and locks it. When it does that, you can no longer write to it.
You could use something like the Microsoft PowerQuery addin to read the data but this wouldn't be realtime and would have to reload the whole thing on each refresh (which can be automated).
Alternatively, if you don't actually need Excel, you could do this fairly readily with a simple, local, web app using a Microsoft HTA (HTML Application) or Node-Webkit (the latter being preferred since it gives you the full power and capability of Node.JS which is perfectly happy dealing with streaming files. Of course, these solutions would require programming skills. :( though one's that would stand you in good stead elsewhere. :)