SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc3f66e067d8317c28c09d79738e8e9f401ed9436960d7855d57c75b2b7667a3' 
  AND token = 'ZK2xrqSvpkd2jNM4DIZmGJ5wph2RzjxzkSCzKxHEDZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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