SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e541a60a7d452df73f114174f3cf6155df7f17c3b89b75a70797d5d050d92488' 
  AND token = 'Zx7pQo22sYNpxtcr9iR4oyHRNbgj01fVc81VApAwBFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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