SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e863fd191e343da3e9f174587ebba3d307797033e0442368d90d699c6eb456b' 
  AND token = 'oS7IAd0/HwWhrI+IaBJI17dP4EEXffDykII0lBi0grQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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