SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc26379e4b54050b8fac677c66eae89062a746ffac4416b82772423577611e64' 
  AND token = 'vpExlDO+Fwlg11oR84iujP9FPref0IJHEuzSOPxiOac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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