Texas does not require any breaks at all, paid or unpaid, for employees of either exempt or non-exempt status.
You were not paid at the rate of 40 hours per week. You were paid a salary based on the value of the job to the company. If you are looking at payroll records, be aware that many, many payroll systems default to show 40 hours per week to exempt employees, but the number of hours worked by an exempt employee has no relationship to their pay, regardless of whether it says 40 hours on the pay stub or not.

