@keyframes anim {
0% { transform : translate(50px, -5px) rotate(0deg) }
100% { transform : translate(50px, -5px) rotate(360deg) }
}
#barre {
width: 100px;
height: 10px;
background-color: orangered;
border-left:10px black solid;
margin:auto;
transform-origin : 5px 5px;
animation : anim 5s linear infinite;
}
<div id="barre"></div>