SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd4e1166c5e482b3000f150795809306bc5aa6f94aca4f39f34faf6e9fcc64112' 
  AND token = '2sdzEj6fplErRsFCd+hTKuDzmeRvyIjvsnBROVzpt3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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