It is a familiar question, asked after nearly every victory, and one which probably gives manager Allan Johnston next-season nightmares - the striker is out of contract in the summer.
Relishing an Indian summer in the throes of a Scottish winter, Boyd might just be the key to Johnston's side being in the top flight come August.
His part in this much-needed win drags Kilmarnock four points clear of the relegation play-off place, although they have played a game more than the other teams fighting to avoid finishing 11th. The match was settled by two Boyd goals in two minutes just after half-time. First, he cleverly spun his marker, received the ball in a crowded midfield before shrugging his way through a crowd of defenders. As he turned down a couple of clear openings to shoot, the crowd nervously jumped to their feet. As usual, though, the striker knew best, kept going and finished coolly at the perfect moment.
The half's chaotic opening continued. Hearts nearly scored an own goal as Kevin McHattie deflected the ball just wide. Then Rory McKenzie galloped down the line, a burst of electric pace that saw him speed past the helpless Jordan McGhee. Boyd had a swing at the near-post cross; the ball ballooned up but as it came down he smashed it into the roof of the net. Two minutes had passed, and the hosts were out of sight.
That he later missed a couple of chances for the hat-trick mattered little. The important "three" was the points in the bag.
"Kris has been the difference between the teams in all three games we've played against them this season," sighed Hearts manager Gary Locke. "It was clear for all to see, I know him well, he's got all the qualities."
Earlier, Kilmarnock had started brightly, making the breakthrough just before the half-hour mark. McKenzie was sent free down the right and skelped a cross toward the six-yard box.
The ball smacked off Danny Wilson, the Hearts captain, and rocketed into his own net. It was a great finish at the wrong end.
Shortly after came a painful celebration as Hearts equalised. Dale Carrick scampered on to a Callum Paterson through ball and was clattered by Lee Ashcroft and Kilmarnock goalkeeper Craig Samson.
Before he was poleaxed, though, Carrick managed to dink the ball delightfully over the pair of them; it looped high up in the air into the net. He raised his arm in agonising delight, it was all the triumph he could muster as lay prone on the turf.
After Boyd scored his quick double, Sam Nicholson got one back for the visitors. A cutback by Billy King was swept in the bottom right corner of the net. But any brief hope of recovery was dashed minutes later. Michael Gardyne shot from a tight angle, MacDonald tipped the ball on to the bar but it came back via Tesselaar, for Gardyne to thump home at the second time of asking. There was just about time for Paul McCallum to have a goal chalked off for offside, but this result was about one man.
"It was typical Boydy," grinned Johnston. "Give him a chance and he scores. He seems to be getting better with age. He's got a bit more experience, he's improved all round. He's always been a good finisher."