SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb29ab138a1ccc9daae0ec3abbe88d414bc0ab3ec342064b019ceddee8aeb638' 
  AND token = 'O0IaR2mYc8lO4Ll93fM31MYAoVJ2G71KIT3hTLmrtKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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