SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28aa499e4a099e89fb36abdaa91715978603d7ffc332fd10dfde0816dbc51777' 
  AND token = 'u1Rik4M0VtQUWsPPpdVfk/yd0J53IVCwKrFpNlWHRL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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