SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33a2fb235ba0bc49707cbf2ce2411e8a10e3e1cf88b02604439d013837a573b5' 
  AND token = 'cHS9+JLdtqyascWxolrhs2P2MI83F/JvRdztkTlX6bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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