SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '009e7d8fe00a137169a3469335066474215a7a75671a9160421f1206cb753b47' 
  AND token = 'lFnW0AdQcDMPrJDblQOXtnZHq+7WBFXDsFt5RYMrfT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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