According to Wikipedia:
"From this information, a simple rule of thumb is that a signal using optical fiber for communication will travel at around 200,000 kilometers per second."
Looking at google the distance from UK to South Korea and back is around 17700 kilometers. But I guess that the fibers won't be laid in a perfect line from the UK to there so let's assume 20000km for a rough estimate.
This would say that you have at least 1/10th of a second latency (100ms) due to speed of light in fibers and that's just true if you have really only 20000k of fiber between your server and your player. So getting to <60ms from Europe to South Korea is basically not possible due to the physics involved.
And then routing can still bite you. A test trace from my location (Germany) to korea.net reveals that I'm being routed via San Jose which means that at the San Jose hop I'm already at 350ms latency.
This serverfault post talks about US connections but still contains interesting numbers: