SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df03bcc020e9f466a4a2588720cbd3e0b91ee0bd03eceda8c3fddae6f2ab5d32' 
  AND token = 'Sel1v9K0+BUDl0VwCZ9Zv3QzeX8+F5h8DMRzKGucRXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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