SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7bd4338eded7837516d677cd9ee836f8187ff2d6f0ab40a12aa628f761e06f75' 
  AND token = '9B67HpzMhElDVlqqS3DG99uuLANjWv1wjKzJUnWayiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}