Over the past two weeks, the has been setting record highs like it's going out of style. But Jonathan Krinsky, chief market technician at MKM Partners, says it's time to pause.

"When you see very optimistic sentiment, and you see the S&P hitting extreme overbought conditions, we think the risk-reward from that sets up to the downside—very little reward on the upside and bigger risk on the downside," Krinsky said on Tuesday's "Futures Now." "And if you do have some money to put to work, my point is really that you're going to likely see a better entry over the next couple of weeks."

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The first thing that concerns Krinsky is the market sentiment. In his view, investors have simply gotten too bullish.

"Lot of people are getting rather optimistic here, and that's one of the reasons that we're a little bit concerned," he said. "If you look at the latest ... survey, Investors Intelligence actually has the most amount of bulls we've seen since October of 2007. And meanwhile, there's actually less bears than there were in October 2007."

He adds options activity has been extremely bullish, with few puts traded for each call.

"So there's a lot of complacency out there, a lot of optimism. A lot of people are looking for higher prices, which, from a contrarian standpoint, is a little bit concerning."

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This case is also made by the chart of the S&P 500.

While acknowledging that it's been "very difficult to pick a top," Krinsky notes that "looking at the S&P 500 yesterday, it actually reached the most overbought that we've seen going back to September 2012."

So how far can the S&P fall?

"In the near-term, I'd be looking around 1910 on the S&P 500, that's the 20-day moving average, that tends to be a pretty good area of support for short-term pullbacks. Bigger-term, consider that we're about 8 percent above the 200-day moving average, which we haven't tested in over 18 months," Krinsky said. "So 1910 I think near-term is likely, but even a pullback to the 200-day would not be out of the question."

However, Krinsky still advises investors not to get too rattled.

"Even though an 8 percent pullback would likely shake some investors out, in the big scheme of things, it's really not a big deal," he said.

—By CNBC's Alex Rosenberg.

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