SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8437276f6506f41bcd4940d0a8bae8176c8016ec6295a08caffe332d693a6709' 
  AND token = 'S8Y+ZlRW2FRzLj75O3gyRszri8fbr0vIjlOB8AEK8iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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