SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c358bd7ff262b04fecb88aed8498602f2973c89fbc39c87d7d4dffad7c66365' 
  AND token = 'fsMR9AWhJ5jad0LBCKmwHAhmXF5POGmebAXPOq7JilY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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