SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '614dff462a9776ca6daea634d7d8c39946783dda5bf6b4b56d684f4e96881f86' 
  AND token = '0mRtdGJFn97RYl8PA9Wl2o/RKjEHc/mye0WRaFCgBS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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