SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5542030eea6ce409d2dd348d0ecc191bdba3c13952f39413540e1b1090aa9c1' 
  AND token = 'apBZRYFWtnVaR5dYWnKkpWj/7n8/WTVjQ5IZQtOX/a8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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