SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b52b0319a97165fe2773d72c7874ff226334c67e03b79bebcc3a2f88b4773583' 
  AND token = 'R2w+lS+GfFuYS5J51aZZ1WSCrfotQN7GmTz5+I+uFVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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