SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf379eb83b3228ddcca575a65b071fc0794d242d5ae693eb9b6bb55d51d866e' 
  AND token = 'nj9eHjt7DflwP0nJSfJ5+lFYvk0Jzc5VHQ+vxGYxBik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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