SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d76c3635123b752de025c7ebf884f1617d4b29dc4f66e46daea3eeff42eab72' 
  AND token = 'pvWaAX4atoRKt3tjVIISer++oNiYeU67qmFpl2pWEBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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