C.J. Gardner-Johnson's Mom's Restaurant Hit W/ Bad Reviews After Kelce, Swift Dig

11:56 AM PT -- C.J. Gardner-Johnson's parents, Brian and Del, joined Harvey and Charles on "TMZ Live" on Tuesday ... and said they're not sweating the cyber attacks one bit.

In fact, they told the guys the joke's on all their new haters ... 'cause King's Grill has actually been closed since late January!

The two say they've become owners and operators of a new restaurant in the Cocoa, Fl. area called Village Bier Garten in wake of King's Grill's shuttering ... and Del's adamant they're "going to be fine regardless of who posts what or says anything."

"We're good," she said.

Del and Brian say they're planning to attend the Super Bowl parade in Philly later this week -- before Gardner-Johnson is honored in Florida with a key to the city.

A restaurant belonging to C.J. Gardner-Johnson's mom was bombarded by an onslaught of negative reviews on Monday ... a short time after the Philadelphia Eagles star took a jab at Travis Kelce's relationship with Taylor Swift.

The CJGJ barb came in the hours following Philly's dismantling of Kansas City, 40-22, in Super Bowl LIX. The defensive back shared a photo of him in front of the tight end during the big game, and captioned it, "Should've Stayed w that thick s****" -- an apparent reference to Kelce's ex, Kayla Nicole.

Seems a bunch of Swifties and others in the Chiefs Kingdom didn't care much for the swipe -- as it looked like many of them raced to leave bad reviews on King's Grill's page.

The Rockledge, Fl. eatery -- which is owned by Gardner-Johnson's mother, Delatron Johnson -- was repeatedly called horrible ... and slapped with dozens of 1-star remarks.

The avalanche of reviews actually triggered an "Unusual Activity Alert" on the restaurant's Yelp page, and comments have temporarily been disabled. Google, meanwhile, has appeared to have removed all of the recent reviews left on its page.