SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78d798cc3254035f92dc8b3fbd4dff084c7759bfc7b4b780ced222d8b9c4592e' 
  AND token = 'LVV0ED7zWeJ0LjnvaZcTmFejUMprikSl7ANrykKnuNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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