SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f47aa423625951b14844d1034fc866e02eeff747e6a7149df99d0898b73710b' 
  AND token = 'NXQEiTZxwx2lTV1TVWPwdN+phgwLWn+h0GVqrV+OpUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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