SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5a64abcf83f245d6b2a3e8f046e1666a204397ff6917b4d869b632a44b225b79' 
  AND token = 'eFttxzgj0VgzsBTfIcpyOrqaMcAgXiIAdbWqje4e+NA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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