SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '332b287367ddbcfbe43e1309d6c068615b9cc0a48b96048db265649a8ab3f876' 
  AND token = '3+kyHBhOFmUJQ55gcOG8yiQEvnzzYxASAC/2MsDXjRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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