SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bb3b1ddf71fc9f315e003a322ea9dad4b05b0b084140a8cdfe560f54c01c12c' 
  AND token = 'DJaFMtFDjdi+7HxEkXZdrxCaf43oOZl9kfHQRx84nos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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