SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '820b9d7368e2ecbc1401918a372a1f39e17aa76b59ecb5af5c9c826833d4ff41' 
  AND token = 'JEFfNauePSlY/n1M6rFVLWFIxdXUB/fp4itW0WnBMbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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