SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '80e542b95192feea6bbde6c42c78b76068ae422c67b5affc319a1ff4b0786db3' 
  AND token = 'DF3DUKC9ZwbaY6VdZBXs5yTzzQG07TfpheHOgZSzlZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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