SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ffa0970165741e13ee43e925f725a8d5efba861790986ab3efdcff9ac25384d' 
  AND token = 'BTh3VYRNp5GXDwx6zK/NRI9xuhIPyJN+DOgFuOOOj0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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