SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3e673cf9b62526144c74cb526c52a3ac8d2417814d12d0399082543e46e9c73d' 
  AND token = '4nTmQa+U4gGDJq49kuDgQduFI/Js6iEV8xrjAVMzfzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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