SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9bb39f7e92287ec3465f4dafccf183dcee91a5297b38413ac5f54589348f9a9' 
  AND token = '9E6Ka8oGVktv3yWJbS8eHY16yYmYaiyNnysmz50J7Fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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