SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd47a856c290607549eabd538cd0a02b4dae31762a662ad5c714a53a6e141d660' 
  AND token = 'nAw5VT52I/3WJzE6cKQElMMGTdr8BjKRCkTeu7QfCOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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