SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '19c8c2008016271c7223be8dbf73d2b7349bb4ab2a9365e4d538930c2c55113f' 
  AND token = 'd7Orqnso7FSvRGDo/QUZU6tvSc9UvzuUBeyn7jN8Yug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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