<div class="progress"></div>

.progress {
  width:120px;
  height:24px;
  -webkit-mask:
    radial-gradient(circle closest-side,#000 94%,#0000) 0 0/25% 100%,
    linear-gradient(#000 0 0) center/calc(100% - 12px) calc(100% - 12px) no-repeat;
  background:
   linear-gradient(#25b09b 0 0) 0/0% no-repeat
   #ddd;
  animation:p 2s infinite linear;
}
@keyframes p {
    100% {background-size:100%}
}