SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c927a1a5144624dcee9297987a1d528551d556ea926651c3a83117e4655172d' 
  AND token = 'MAAkYeKYiVA27V9P4nBNu6AGfr3WMNmuR+na3JhN/Ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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