SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d47a117264e39193a71be65c7342bd24b9a6baa3503fbbff6093a772b1a5ac4' 
  AND token = 'tjGdn+DJzHPFYTlMsb7jkxstxhj66imjMXz95o6UIWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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