SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49bef5f0b8372b0afe65040b7db2784b7ad1ecd8fc0825cf429ace177be0320' 
  AND token = 'I0r9HOZRVqfkJxdRFFWXjxT2ow+K+j8PcZXKfFyc0ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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