SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc052dc29738ca79ed4a4ac0e6c9d32bd18ba8dd12f66ad8bac0d07ff9194dde' 
  AND token = 'xI0g5bbFyCUgxsv1XFMZxjPUiqM/5xASzJjtMfIZBFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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