SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '323792ba1dc0a338de5a757a93c3091dd9369d4e97feed4e3bf89d0be9eb66f3' 
  AND token = 'uFgoN15cOuDksdqI8+zKuZWpE+mKALv6MkTkuw2XzLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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