Item:

https://backpack.tf/item/16180927591

Sale:

https://backpack.tf/profiles/76561199697394581#!/compare/1770249600/1770336000

https://backpack.tf/profiles/76561199761324539#!/compare/1770336000/1771027200

8 keys

The 8 keys histories either have 'Unusual :D' or 'Tony' in their histories, the buyer 'Evaneitor666' dumped their Drunkard Cattleman's Kettle to 'Unusual :D' and their Schadenfreude to 'Tony', dumping these two items and buying the KaW Kettle are around the same time of the day as well, so pretty obvious they are the keys that 'Evaneitor666' used to buy the suggested item.