SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6a80ef597edeeb34a6d18a9587cda2efa6ca92254f83c1919931387125037a8' 
  AND token = 'OOeqPBw+/eHIzTzYUPtYylzIfj0e08pVwMeA4YQIw5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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