SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '39571f6d25f71d24b5ce2714c3ea9c64a106afc32a15896eb78c444a65ab73df' 
  AND token = 'XsX8aUxW5vL1KMLoXe4yTGvucHwy7rDBAPZJVCQezdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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