SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38a5cf37de39b9809f54f0d654fc17cfa24ec56b2a1f13a5b48c5cf4daa67f1d' 
  AND token = 'V3vWpx+BgcI1dwF7P6KYHGLiCeCn+vjCoUctqQeTVpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}