SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b1c7e128d409c6f71f10495a6645545e335c558856ecbfd3f23c32a5305d8b6' 
  AND token = 'bejnJrbO5jFnWRtH9azP5qgX0sUSbWFb2AJTIHMdNHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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