SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82a2bf6e0e126bb4ce4212acc3bb74f196dfccce2b37a4dab96e016e26283d35' 
  AND token = 'SZgqWtZaBpEn+Pqp1Vi5TepRHMBuJyC6hkNCp4iSfxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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