SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd1738e87d1db207ee611afd4a54aaf5c8f39783e324775949ff3745d83587e7' 
  AND token = 'LPYA8tK2Z5xj96cGH6ZpYXFJLDP4gZmmQjyc1lzDYMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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