SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9b5273d45fedc911286604298546a51d05b669b2a29e957380cc73968e0e08ed' 
  AND token = 'MqJNn6P2mz+AsoqNolC4qL7OrlzZhAyTo+WeXtVwckw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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