SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd725d39ccd38336a78069970bce32c381e96dbed47a8165eedb0e0a5f6343d29' 
  AND token = 'PfgTEQvNl499orbKvtkBN4hKDYkTBYtxL/EQ53yQklk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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