Ruby Reads ' Noah and Santa's Special Key' by Sian Phillips.

' At the North Pole, Noah loves Christmas, but this year feels different; he's struggling to find that familiar sparkle. When he's about to give up, Santa's note reveals that a magical key is missing!
Wit his reindeer Blitzen, Noah begins a fun quest to find it. They follow clues, ride the Christmas train and discover festive joy. At a glittering Christmas tree farm, Noah finds something surprising that changes everything.
Join Noah and Blitzen in this magical adventure and discover the true spirit of Christmas!'