a {
  border-bottom: 1px dashed #cecece;
  padding-bottom: 3px;
}

a {
  position: relative
}

a::after {
  position: absolute;
  bottom: 10px;
  left: 0;
  display: block;
  content: '';
  width: 100%;
}

<div class="basic-single css-b62m3t-container">
  <div class="select__control css-1s2u09g-control">
   // ......
  </div>
</div>

.select__control:hover {
    border-color: blue;
}