SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3609a82ba029f3705b84375be65a765f91eb3a76f776416ebdf498859c3f6a56' 
  AND token = 'KxYAPiV+Ycy75UEqrKpTMRxwW/RfhTqLYV1ZtjRVmas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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