SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33ff2be234a98a9af21645e8987e612cddf6d7639386f1e63284b675d7111dd0' 
  AND token = '5CIps2WxjnCTsFLjvB5DZhK0iKJsdZi4Wmq1Ow+kydU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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