SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b9a1509f8ee50db1909919ed59e864961f259e40bf592182de4be95185999d83' 
  AND token = 'Hi6sqdtksKn194pzVE930Mz7R69ZrXZwoi/f/PnK44w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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