SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1d0ff0289aaa36f43b547b49ec62f613b1281f3b66ddc091ffa334a33a202ddb' 
  AND token = 'DTz+zeo8taFcY7kaN6JXeWBSiHXaabUOuX9OCNG5CJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}