SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a36a34d33f0fa3ebdb07314c081ff339515e840dc62b249f937180fa15d800f' 
  AND token = '7fWXQAwNn52pEv+j+1DYArYm48HoEpwwL7ldPoyZPxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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