SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c6f7be7847135e95687d3bbc915ee90ee7022794fecd39920124b55926a4a81' 
  AND token = '1fh0jNF3xEswrAPuDTjqK96zqKRM5HWVBkU7o1fDMoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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