SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9acc6df0faf937a6ecb4d51cd49fe23b616c4f38eb899982ac335e4e45cae717' 
  AND token = 'Zuu+pEwPzYtfJ1IdrpYiEKTNnIH2WMR7Hig3qauEvOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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