SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76f3ff0ffecd6586c1fc2bba7c80a642d96b1f912a25f743a13818945ccc9e96' 
  AND token = 'o5Pcz8RZqP/4fC5bH/zWjzYYvTyE33cpUujLDdhA+lM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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