SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4efbf338095fbe4c97d52ef316da398961c132e98f638b6f0d90ed406d06fc9' 
  AND token = 'oPRY2oFCntHyzGUjugdW3gvzldUyHwZGTIGG5o7vg2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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