SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '499a4cc519c6f83ed9065dcc0d3ac9232f47a494ffca2245979e6796ebcd1df3' 
  AND token = 'D9TFuM2yZIPi6aZ+Ju5tMKMlEqWJVMncu4IqLuYdkSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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