SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a1a7215c85c3e55e946f6ba77d23331aa2e2c08e7fc9e66817a1bcfd7a2728' 
  AND token = 'Wa7y/KpEe9vyNslyHqsG+sd0HnsTFOxz2kAnpRznyy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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