SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8f429e861f026c51a56a6845d7d7496b92f07fa390932cd3329a613cdd890fe3' 
  AND token = 'vsPZoqx6USsRhXxego1LztXdFyzLUaHGcES+7ljAP4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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