SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '023f691a20d70c55ad109d6473d8282993e854311970198b62e8751bbca58f1c' 
  AND token = '4AyaW3OL/U7mi9bLBTkAjk7zsjZ/a2W0UlZy4T9xKxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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