live for the moment

live for the moment (concentrate on what’s happening now, on the present, with little or no concern for the future) — жить сегодняшним днем; жить одним днем; не заглядывать в будущее
live (only) in the moment

Example 1: I may be wrong, but I’m not going to worry about the future any more. Instead, I’ll be living for the moment from now on. (English Idioms and Expressions)

Example 2: Instead of putting aside funds for the children's education, Jane and Jim live for the moment, spending whatever they earn . (The American Heritage® Dictionary of Idioms by Christine Ammer)

Example 3: It is deeply disturbing that the majority of people that do receive a basic education in the western world turn their brains off the minute they leave high school, and live only in the moment. They don’t understand that we need to keep learning, progressing, evolving.
(Space Exploration as Education)

Also
[жить одним днем]
[take it one day at a time]
take each day as it comes
[cross the bridge when one comes to it]
[get a life]