The Blues hold a 3-1 advantage following their first-leg win at Stamford Bridge, and look likely to reach the last four of the competition.
The Londoners face Manchester City just three days later for a place in the FA Cup final against either Millwall or Wigan Athletic, but Moses says that they will cross that bridge when they come to it.
"We'll focus on the game," said Moses. "It's the Europa League, it's a massive game for us. We just want to put the City game behind us at the moment. That doesn't come until Sunday.
"Rubin Kazan are a great team, so we're here to do our best. We're very focused. It's not going to be an easy test for us, but we're looking forward to it. If we can score an early goal that would be great for us.
"Hopefully we'll do our best to try to win the game and get into the semi-final."
Chelsea face Rubin Kazan at the Luzhniki Stadium on Thursday night.