If the mind remains in the now, it's impossible to worry. People worry solely about an event that's come to pass or one that may take place in the future; the current moment contains no time or space for worry.
Keeping the mind in the now, unless we consciously want to contemplate the past or future, it's possible to face life without fear. There are then no thoughts of past failure or future hurt, and a positive mental state results: fudoshin, the "immovable mind."
— H. E. Davey, Living the Japanese Arts & Ways