SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6618863fdc66b0fb30057074f8e89ce3d55433e6f1acc9b8d0bce6c85aaa2209' 
  AND token = 'kUexhT9w8M0VJTTuVijlItW5/PLrbDVaXvBbjUP9hFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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