SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c1b15529af3cc6018acadc7c63c8d383aa43f5780b3742b79692c7379771f2c' 
  AND token = 'lkfHzb3xIrK0DakJ3GOKgBFBoz1JviMqGQX5VJtMz3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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