SELECT 
  1 
FROM 
  q_lock_keys 
WHERE 
  key_id = '838b87871db066bfaf2bf1c9d953841c364d69f94fbc58d5a880170edf0e4c28' 
  AND token = 'Dz7jnJFu0T7j5YfVyWdxbaZfpToaJ5fVVgvMOhS6r98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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