SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '551c09825ed70efd138a36f13f76bebdb8f7051f05bda8fc787be56943177eb5' 
  AND token = 'tV53BlG48EA1HZf11gpbOl5kJvY5qRO67ZrTLL04bio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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