SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f640f006bdb0bc5008f2edfddc39f23af279441b13fddf9f4594c94928321610' 
  AND token = 'MlxvuZc64YTYJDYxZYllMLGklaeYkJ/2ge3xeFZQffo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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