You can trade NAS100 CFD during London or the NY session, depending on your strategy. It is possible that you might have a better strategy that works on NASDAQ during London session.
NY session is more volatile & you will have faster & more volatile moves.
If you are from Kenya, then you can trade NASDAQ from 4PM-8PM, if you want to trade the NY session. Or you can trade between 10AM - 1PM if you trade the London session. I've plotted both of the chart to highlight the last 2 trading sessions, so you can visually see both.
It is important that you must first have a strategy for that time & proper risk threshold (account & trade based), regardless of what time you are trading at.
There is no one best time, it just depends on you as the trader, do you have an edge trading NASDAQ at that particular time or not?