SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f256163727c77e6651cf56e8a657bee7cc3f81a42bb05058098afca056dd1cc' 
  AND token = 'FnOWT3djWjGv1bJSp8+lsCLFLNOhPOGvsRNSPlU6cbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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