SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff8cf8b2648203270fa3ed2182181d84fb39b57b8078ea13736b9d614f8d38f' 
  AND token = 'xav9qLpMD0eTbmYFLMLYm5tvNV7nEbGUbFtzIs5omZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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