SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86536e6940b4c24dd92fdd1fd5bb40782ede6856b9fd817a9eedc1ab7b0f4620' 
  AND token = 'bDlqmuleCRpQLx6TWnDQzry5o4FIfSbdDNbDw+HMGhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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