SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3820cdc5a4177740ba48d6976d818f15288fff7b0783f8d841fde113bc65d6f' 
  AND token = 'bgYwnWmi/f281Q5hBGHdDXnHMqyp+qAdFMJUBxooXMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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