curl --request GET \
  --url https://mainnet.mirrornode.hedera.com/api/v1/accounts/{idOrAliasOrEvmAddress}/allowances/crypto

{
  "allowances": [
    {
      "amount": 75,
      "amount_granted": 100,
      "owner": "0.0.2",
      "spender": "0.0.2",
      "timestamp": {
        "from": "1586567700.453054000",
        "to": "1586567700.453054000"
      }
    }
  ],
  "links": {
    "next": null
  }
}