SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30e638db7fe03f7cd82c4bf8f66285211a90b1a5c095a28d71f30da9bece1795' 
  AND token = 'sYXdhQHqFKsXXU+TMkWHiZxv7tS10g8jiWNDT5zeV3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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