SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ca34d9dbe0f780b2137a2732595389fcc65168ec77f91c2b8b8d5eab7ea6cec' 
  AND token = 'z/+oEBmp/9ghf+cMaVlDrBnZ2GH6UFK9wvtYvuHmQLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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