SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79bed7860109926ae73f29f055f7cc77f1b85ce3702d1dc6f48bedc7f638f587' 
  AND token = 'iTR23e/09uIeX+lrTw0oOL6JFolIBYoL3olWJ8X+eLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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