SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82838f2f1ba1ab3efe9430dedeff4eb4263a36cf8ddf2a13ec57fbdfde11f243' 
  AND token = 'z5e0hBxhCegZLnxJlxqMkef5T8mNsgtYuFLMSDlbCW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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