SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '525a3faaf634e26991dc2050f6be48a63073e05a5ac46cb86e2985b79a4bfdcf' 
  AND token = 'bKgoR4RBBZ2d6t49KvkjVrHbxBVxwCJthWILzmD7cks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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