SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f81876b0efa35192bfa74529c4c93cdb0af80e9942ee87f7ea7c68b142adfdf6' 
  AND token = 'GgDUpdJcfZaefYYSV/YG8hqLWlHCrHu/aqh3vsy+PXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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