You can ask, but they probably might not know what it is. My guess is that they don’t really have shakers and things on the cart, only in A380 bar.

Especially with English pronunciation vs the Korean (more drawn out syllables and stressing)...can be a challenge. The first time I ever flew KE in economy I asked for a vodka something and she had NO IDEA what I was asking for. And it was BASIC. So try it, but don’t expect it :-)..