SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66bf0347ec11b1c29063883e084288e5cc9bd1ff08678d101f4a65d98a5cc279' 
  AND token = 'pyhgfEFlxve2nal0wTqJa5lMsHRUhGmgcGTrF0ESjEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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