What is the meaning of 送上 here?
送上，送给 both means send. 

Two differences：

1.送上 is more polite。


in different sentence structure。


a.   为 someone 送上 something。

b.   送给 someone  something。

This sentence equals to ... ... 送给近百名员工一把找到工作快乐和取得成功的“心灵钥匙“。

reply to the comments.

心灵钥匙 is a description of 讲座，it is a metaphor.
This lecture is the 心灵钥匙。

examle
学校组织了一次军训活动，为广大师生送上了一次军旅体验。

军训活动 is the 军旅体验。