SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96ccd22c153553c9cef600347d0d65b4d58f45370f49c9f4560b08759424c8ac' 
  AND token = 'FUGstNXT5ApRVQKOc+nCsUwnUuipYkrwUC3tEx8U8CM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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