SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '80e8749051782b4aed03fd8a42990f175967d34329147add917b1ee97a3a5985' 
  AND token = 'cCEcNCBSpa/19WXJYq2liRI+pfF/4WeDr7BncGqZfys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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