SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac24c87c8f2aa9c93cebebe1a97adb319a4e4a5ac2df379dbf1c1992a885fd95' 
  AND token = '3bfuIvJrrOmNix7rwKSszyJfGsTz0JaSEan+AKvffYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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