SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9a5b7e1e6fe600d75be9b2941d7666dd52d8a48c464d2c71edab747563ef2fde' 
  AND token = '/oCVUPJEvqMhkCYyOG0638ofGVCz5UtclWgnN/Z6kNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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