It’s rich of Tim Key, his agent tells him, playing the underdog “when you’re lighting up cinemas with Carey Mulligan”. But play the underdog he does in Loganberry, his exquisitely tart and amusing take on that standup staple, the midlife crisis show. Other comics invite you to take seriously their existential wrestle with ageing and insignificance. Key’s is a game of cat-and-mouse, a twinkling ironic tease inviting us to wonder how lonely, furious, insecure – and indeed how old – this acclaimed comedian, actor and film-maker really is.

The trigger for this descent into forty- (or is it thirty-) something angst is an invitation from his recent House of Games opponent, sports presenter Gabby Logan, on to her podcast about middle age. Key is outraged at the implication, retreating from the microphone – as he does throughout the show – to bellow at the rough justice he receives (“Where’s my MBE? Everything I do is for this fucking empire!”) from life, the world and his uncomprehending public.

In trademark rumpled suit and greying hair (sorry, Tim!), he prowls the stage, circling questions of age, self-worth, his celebrity status and singleton life. Structure is provided by an account of time spent in a cafe, struggling to write another “58-minute concert” for his demanding fans. Greg Rusedski pops in, sending Key into raptures (“Full tennis WHITES!”). The red-and-white checked tablecloths prompt rueful reflection on our host’s hobo-like, “stick-and-bindle” life on the road.

If midlife brings few consolations, one must be Key’s total command of his unique style. The scrambled signifiers of high and low status; the smiling, ever-so-faintly sinister relationship with his crowd; the ambient background music – and all those banal/beautiful haiku (“Colette gave birth to an adult …”) that again punctuate this set. Key has them all where he wants them, while ensuring we never quite do – and part of the fun is unpicking precisely what he’s up to while he’s making us laugh and laugh, at tales of freezing his sperm, measuring himself against his parents, failing to be cast in Ted Lasso. He may be lighting up cinemas, but here Key casts playful shadows over that glamorous public life, in blissfully funny fashion.

At Pleasance Courtyard and Pleasance Dome, Edinburgh, until 24 August. Then at Wilton’s Music Hall, London, 10-22 November