SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bc31c597281962a2ed0deee627f302429f109e27e3762835756b2b9458aab0d' 
  AND token = '6gXBjAg6/LLgmfgH6A22gLy4Xg6bzSp6CVRjRIXi5r0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}