SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34665dd0f85430090427076d8af802f6a662d4b134996dcc3ea92c66f7d1887b' 
  AND token = 'LPQyovyc9DLgs6BUFLL1m8RRzs6TVIwxsnbvUSMY484=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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