Please don’t say this.
While the intent of the phrase “I’m living the dream” is self-deprecating humor meant to carry the small talk until you get down to business, it comes across like you hate your job and would rather be doing anything other than what you’re doing at the moment. At the moment you happen to be meeting with your customer. Why would they want to work with someone who feels this way?
Instead say you’re doing great, and believe in that; or borrow from Dave Ramsey and say you’re doing better than you deserve, which is a stance of humility.
Either is better (and classier) than the equivalent of “it’s 5:30 somewhere!”