SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ce785e01959c4f2626b48aa7fa909f6cb18dcfe9aab04ac4df8fa379e1b2a4b' 
  AND token = '/QnW2ITBEymZUvfDRnjcwPbY7FS8RhDlx0WAwtMBOR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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