SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '355e21e051b9aa1a57840f7d096c17e76c3ac098a90f8451ba4aa4b40adff28f' 
  AND token = 'qnqSBbP2VSyyYFr/42fgzbi94iAzVZpeW9oPdDGIpa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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