SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28996bbf0074b1d9508b67eb82bdaa1732ec002950b35064bdb16ad65806512d' 
  AND token = 'TEKpzSq2vE8RSvydIrYnDWuXUxv4MNAaz/yQsdXw3p0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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