SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3758faa8aa72a8e123f2eaa8ed52ee2f0696e75ababc55146f7eee31bf5f2535' 
  AND token = 'CCFbIZ5PkGwKUJqQYoWU/1LBVrEfCi5fAVdX3PsJXxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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