SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c86e8f82e2f703be8c7bb1fe3acdb8264e1604249d2d99504acf01b86d525e70' 
  AND token = 'bG6QundcAHkIBY6wPCbtvZlITjRrPeAuWpI3RwssShU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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