SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2e981b834c1f44e30d5666eccc377c817cb7e77ab6993a6c63b022c37ef3649' 
  AND token = '7+XoHnhIKFzLqndIzg/5qyf9fAxO5SrHsLjpgPqRX/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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