SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf10f20312f49947ed84fbf231c8ef6cf0bfeb01092af6b572d674bf32255173' 
  AND token = 'RsMmXc4rBVqna4cjE7xd+bG7/PdAzN9X+cS8lWXhDUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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