"脚底有厚肉的" can be translated as "having thick calluses on the soles of the feet" or more literally as "with thick flesh on the soles of the feet" (though the first option is more natural in English).
"Calluses" refer to the hardened, thickened areas of skin that form as a response to repeated friction, pressure, or other irritation, which is often the case on the soles of the feet. So, "having thick calluses on the soles of the feet" is a more accurate and common way to describe this condition in English.