SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468e2126bd6f85d88a7811b1575334fac00a58dcc367fad829ad38c8c18f3238' 
  AND token = 'BBKPVzHBlmZ6rFEHAAYXHzhQoDJOhWMmhyDAThCUiPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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