SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd00f1a65168b7d17d803d663258786933f2c49378fe43a96afd55999510fc8a3' 
  AND token = 'tQrjJ3hu+D6jpvBHYQXhOewPUeeN3b5IR1BYn5Zz0sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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