SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f52b817828c27973f64749cedd36c6853f34a1fc8a161b10d89b819f43b392c2' 
  AND token = 'ONrlKFe/EcBmRBqX4IvWWfKkw2QJhDXcwgqR2jqHuys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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