SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f71870afffed46e7f43acfe54c893e8821dc4d67d5122a20db78f036e706abe' 
  AND token = '586g8zrva015Diuxy1JBy/kx1ZjX2jqbFZNC7asiclg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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