SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a5ace6582832482742f0ad399631e5ea90ab0ae665f6f07deca7e81eaf97ae0' 
  AND token = 'nu0f7dlAYjCWzRjebrvAnJdy5SkhHTqaSZ7Yx+4KoOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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