SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54306f60a346e9f5c77b2f21791431966210bcb5c3df4121ea314a3f72a2b638' 
  AND token = 't1lqL+N4lvNoupFl43zNJVNoD1vJIVOUu4GyRI9hufU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}