<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" id="green-check">
  <rect class="path" x=".5" y=".5" width="23" height="23" rx="11.5"></rect>
  <path class="pathDelay" d="M6 12l4 4.5 8-9"></path>
</svg>

#green-check {
  width: 100px;
  height: 100px;
  fill: none;
  stroke: green;
  stroke-width: 1px;
}
.path {
  stroke-dasharray: 314;
  stroke-dashoffset: 314;
  animation: goCheck 2s linear infinite;
}
.pathDelay {
  stroke-dasharray: 100;
  stroke-dashoffset: 100;
  animation: goCheck 2s linear infinite 1s;
}

@keyframes goCheck {
  to {
    stroke-dashoffset: 0;
  }
}