SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03d31f98732d826136947fb496152473ec4299f67ca41642ffa033036926732e' 
  AND token = 'sOffpsJwKSCjy6jRGxhGnza563JpPdWcaX0hPSjzwj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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