SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9228af891401114109c4a53f536ab6e6cad709849c8f6c09609406a70f78b9e9' 
  AND token = 'z7IxwNy/jWKX5B5ODGjg5KTgxz8Lo+OuvXk6KtygdbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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