SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ebb5a2e576d75a75eb91ae486395b16f1644c8b92884f7f07ab4305f8909451' 
  AND token = 'luu6uXDo2bSIqTWlgTcoPdnCJSPYuXCYtIfVipe1cu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}