SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a816ffa82bc1727c9abaf7770de8bc1e7bf773d9aa9cdb482bdb5bd7c3b5665' 
  AND token = 'jfqmxxiuD9aLjfYodlChZD8xc3qR0Q5uK8vQe4VWAFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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