SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9b38817e40b221ab830a81c1f8b3378022d1441083deb20f145d4d42102ce69c' 
  AND token = 'GpfRabuZhBTGFGUeUYvPh9NmUvoFi00j/Jzt2NHBQ0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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