SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c321a3b433b9555b5673f5e510bda6bf8ea2da87a39ad446e461f468246cb2ec' 
  AND token = 'kSMHol8C7PzA85/3ou0JhV2gqZmKEN0suOvkwIZz63I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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