SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8740435f21e8eaab75ac9fdcefa30fb85731f18dcf79d2aa759220f01fdc8726' 
  AND token = 'Dn5ze/rNqR+oUXeIFVKzpsDhggavJuu8WmYzOhsTqo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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