SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '851d70ddc09915cc4b7f2fb878ad5f7b8130516e36c610b41782406bcd1a198a' 
  AND token = 'jWyJBImBwMAnJTY/HKXJA7AjB4qZgpqw+BJnmJY8DQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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