SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bbed6082b632462423ef2181734f7efae41efe39af40830eb85474d7ea42ba5' 
  AND token = 'RDWV1IZs6XLTJBC9IZfAAk79pXnwH6H1n7cgIanfm68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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