第一种

.el-table--enable-row-hover .el-table__body tr:hover>td{
background-color: #c6cfdf !important;
}
 

第二种

.el-table__body tr:hover>td{
    background-color: #c6cfdf!important;
  }
 
.el-table__body tr.current-row>td{
    background-color: #c6cfdf!important;
  }