Nathan Williams sent the home side on their way to victory as early as the second minute when he gathered a kick to score in the corner. Outside half Dorian Jones, who really is growing in stature and continues to improve with every game, failed with the conversion attempt from the touchline.
Llanelli then got themselves back into things with an Owen Williams penalty from in front of the posts in the seventh minute.
Jones added two further penalties either side of an effort from Williams before Keys got their second try of the afternoon after half an hour, Nathan Trowbridge crossing in the corner to push Keys clear.
This time, Jones was successful with the conversion and Keys were really getting on top at this stage, although they were often frustrated by the referee's whistle as play developed.
Llanelli responded with two penalties in quick succession, either side of a fine drop goal from Jones as Keys led 21-12 at the break.
The second half saw Richard Cornock and then Danny Hodge sent to the sin bin, leaving Keys to face an uphill battle with just 13 players on the pitch.
With their pack depleted, the home side used centre Will Owen and full back Steffan Jones to shore up their scrum and it more than held its own.
Shortly after the hour mark, and with Keys restored to 15 men, the home side produced a series of drives from close range lineouts resulting in a penalty try. Steffan Jones took over the kicking duties and added the straight forward extras.
Llanelli started to show some of the form that had seen them lose just once in their last eight games as they looked for a way back into the game.
They got their opening try just two minutes before the end of normal time when replacement Nathan Hart got the touchdown for Llanelli. The conversion attempt was sent wide.
As the game entered 10 minutes of stoppage time, the referee issued yet another yellow to Keys, this time to Scott Matthews. Llanelli weren't finished and Nathan Hart got his second try in the corner to earn his side a losing bonus point.
Jonny Lewis was successful with the touchline conversion but Keys held on for the win.