SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ac4f96c4683aa9e3cbd5b9e879ff8043433b13d6c75a22fd8ab6402f93c3d05' 
  AND token = 'QmslmVMd57byoCb9+DmBel3JsikGgyrlmbFolhH+IdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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