SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8bc54d6313fb588efd9971834eb4bff700ad5ccc9dd87413595dcb26f1902c94' 
  AND token = 'P76KU0IVAYDUtun3jy09MYNguOWVkb24oI+G2koVtG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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