HOT WHEELS UNLEASHED 2 - Turbocharged

Quick Modes > Single Player (or Split Screen) > Drift Master.
Assuming you just want the achi done ASAP 😸👍:
'Spinning golf' (01 Mini Golf Course) has the fastest lap time, according to the leaderboards - you can lap in <40s, depending on your vehicle and ability, being sure to drift well to recharge the boost.
Use your fastest vehicle and just race to the finish line - when you're on lap 2, hit the menu ('Start') button and 'End session', and on the Race Details screen you have to Exit (Restart won't count the 'race'!). Repeat, x10.
Give yourself 15 minutes from console boot up to get this achi (provided you've played before and are past the tutorial).

'Graffiti and skates' (04 of Gas Station, unlocked for 2000 coins) also has a quick lap time via an extreme shortcut exploit (41.324s was my Time Attack, #69 on the leaderboard, because few play and know about it 🙊) - just after the 2 green wheelie bins/Dumpsters™️ you take a square right at the checkpoint instead of rejoining the plastic Hot Wheels track, and the next checkpoint is straight ahead, albeit side on (right when you quickly reach it). That exploit can also be used for the 'Now try online'🏆 achi when difficulty is set to Hard for a Quick Race there (see the achi's guide for a video of the exploit).
Alternatively, 'Up and down' (01 Backyard) possibly has the 2nd quickest standard lap (53.5s for me), provided you don't actually go upside down (miss the purple 'power up' thing on the first straight after the first right U turn).