SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '671fe427c45667dc045aa47c55ee073f0f2dad8b42baf0c8b6abb6d15e341c99' 
  AND token = 'LvbrTe5fCPz5po9Q0XmK2OhzSyHb8PibuOIjm6qJDG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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