Yes, HOCKEY is a Scrabble word!

Letter values in Scrabble US: H 4, O 1, C 3, K 5, E 1, Y 4.

Is it a valid word?

HOCKEY is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a game resembling ice hockey that is played on an open field; two opposing teams use curved sticks try to drive a ball into the opponents' net
a game played on an ice rink by two opposing teams of six skaters each who try to knock a flat round puck into the opponents' goal with angled sticks

Also: field hockey, ice hockey, hockey game.