SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e8bba7f71ea1f66b48c3dd240e1c91e350e5b156011d8804fc36d6fd5afba7' 
  AND token = '4Jp/Ryq22yjQ7bLUvxk+KJ7zL8+V2fOgj547ZNGic2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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