Is being able to touch your toes indicative of flexible coronary arteries?

Nope. No correlation. (that I know of.).
No. I am not sure what the link between being able to touch your toes has with your coronary circulation. Being able to touch your toes is more a function of physically being able to bend (i.e., abdominal fat) and flexibility. Further, not sure what "flexible" coronary arteries are. If one faints when touching their toes, that may be a sign of a heart valve problem or carotid blockages.