SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16f1bdbb81518ac18a2d5d9991d858f4347331de797d7b2ccfbb4acf3de33b86' 
  AND token = 'lXmj/qghRBOyA8/Q7fybzA+9BJj7AKhTUTUsGivSngo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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