SOURCE

<div class="bg"></div>
<div class="dot-warp"><div class="dot"></div></div>

body {
  margin: 0;
  padding: 0
}

.bg {
  position: absolute;
  left: 5px;
  top: 5px;
  width: 220px;
  height: 220px;
  border: 1px solid green;
  border-radius: 50%;
}

.dot-warp {
  width: 230px;
  height: 230px;
  position: absolute;
  left: 0;
  top: 0;
  transform-origin: center;
  animation: round 5s linear infinite;
}

.dot {
  width: 10px;
  height: 10px;
  background: red;
  border-radius: 50%;
  position: absolute;
  left: 50%;
  top: 0;
}

@keyframes round {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}