SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21754bd6358883d434f3a4a88f9e27b2324b50c19102686f1c8211b2360e9fcd' 
  AND token = 'u1pSlrs7JpK7XHf+s6V1njl6F1pxG2/lZx4o4+zLBlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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