How much latency is too much to offload mysql?

Hello,

I'm planing to get a SSD box to offload my cPanel VPS, mainly because my main VPS has 500gb of data and I can't fit it all in a SSD box.

The place I'm currently hosting does not provide SSD VPSs, so I was planning to get one at DigitalOcean. However, that would mean about 40ms of latency.

I think that is a lot, but I'm not sure. How much latency would be too much to offload mysql?

Thanks