SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23913d562d4558521dcb288e1eb6b59321e6130c96bc1610d2f707dd1c232d54' 
  AND token = 'eTJHPExDs8zRhgVuLpsghqbGvXPnAB2VZ0YNWF8ZYxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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