I located the marriage record on the subscription site Roots Ireland and it was on December 21 1879. The marriage was in Athy RC church and it was shown as Co. Kildare. https://en.wikipedia.org/wiki/Athy
Father of Thomas was James Gray. Father of Julia was Pierce and the surname was transcribed as Keffe. Both the bride and groom were from Kilmorony. I did not locate the civil marriage record.
Julia was born March 2 1853 and baptized March 3 at Athy. Father Pierce Keeffe mother Betty Duff.
There is a Thomas Gray baptismal record December 1 1853 in Mountmellick RC parish in Co. Laois. Father James Gray mother Ellen Murphy. I would treat this record as a lead.
Kilmorony townland is in Tankardstown civil parish in eastern Co. Laois on the border with Co. Kildare.
Let me know if you have any questions.