SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4111b8b9f380b4a5afe42326654473b8aab8069c2fe7824cf7f949187e6e9111' 
  AND token = '+b94HTgwTaOKzDaMrlT78VmBk71Meb1FzL4mJOmvK9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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