SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc63d5dd53ef316fa415b3ce98fd3a835ca47f9af7941d63df04393e8f2496d0' 
  AND token = 'KlQsYmZiKUciBJGcqFhZzaR9/hgbUoIzsvpnHERLDng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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