Early 30s probably don't need for this Ultrasound Carotid yet (unless you also having high cholesterol) as this scan maybe more useful for those at least in their mid 40s. But if you have some 'excess' medical claim amount, you may discuss with your doc the necessity of it (to build a 'baseline' for the current health of your carotid artery for comparison years later).
I first came to know about this scan when a friend in her late 50s (with high cholesterol and high BP under med for a few years) went for her med check up and her doc advised her to get the scan (when she complained about some numbness in her left hand when she wakes up in the morning). The scan showed her carotid artery is mildly clotted (not serious yet) and adjusted some of her med dosage + advised her to be watchful.
Then recently my daughter's close friend, late 20s, with no medical condition of the 3 highs, experienced weakness in limbs and blur vision. Her family rushed her to A&E and straight away confirmed as a stroke patient. The Ultrasound Carotid scan showed her carotid artery was more than 50% clot. She was hospitalised for a few days and given blood thinning treatment before being discharged with a big bag of blood thinning medicine for 3 months and a review date. The friend (a high flyer) believes her case is due to work stress (since she high income, exercises regularly and eats healthily with no family history of stroke). This is a 'lucky' case as she was rushed to the hospital to treat the blood clot in time.
Source:
https://www.mayoclinic.org/tests-procedures/carotid-ultrasound/about/pac-20393399#dialogId66567473