SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25fcb0337b3769b3824f4c2d48d32982792be820723d2771b6cb2c51c7af98c4' 
  AND token = 'JJH+Jc+glz+DwUkNVh3FHbMjvDumziJh4XZKkZqt6u4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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