SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96cbc4d9d829869026634e12b765e9711b10313cbb9c509b550f1217d264343e' 
  AND token = 'pVwSj8P9oi+J4VlP79Y5ThFWYaFxbPsYeK9KuWwgJNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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