SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4893b36263d5ae31a5f399734205a6efa7735f8b1d8296363dfee85c8ac61f55' 
  AND token = 'j5aGvQ5mpWXDX3XmTqWmzwEViXDWReXoAEyAwq5PdjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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