SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6f9d6ee3473fc0c7dc885f64059b5a0baffa6c91a11db3397013c34f7367cf9' 
  AND token = 'Dy2YdZpSY1aW5P4F1TZpKUmeiKzcc9THLqwmh++SlxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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