SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'adde12c5f1b411a5f01eda44fd451c59e68153802295751a4cbb93e06dfbf08b' 
  AND token = 'zNjNHfMgj66Q1BSE0G6tKC5EcmhIZg//SngqwDil/iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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