SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40cca9631b1c202ad73669df3520bc7a5f1328f90fde5a148defa49451384727' 
  AND token = 'P/ejFg1fzBNhtAV0GerASYanBMiB/9+2y8R2U0F2jLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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