SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c4625ed7eca5c97824a3289f96fd5945e01b5b6012376b7987900b8ff502856' 
  AND token = 'YTUp2qDoXazAegg4Z9Yv5zOhIL22SVBKAYUYgmDX4p4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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