SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5b3eb9937a55b096a66b4f5ca18de920f970f3337a23f7bcca96f07d315083a' 
  AND token = 'c0KfU69KSsLyzrVmu2H2EZRRcctUMHirY6NVEZvvbZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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