SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ae981429ceaa72e5b986be8d79f2d68551fffb8bb916c8af28a9e5ffd349d84' 
  AND token = 'JObzWCIclK++LJ3d/x7VteqHKZ5mcX75/yYZH+B9Xto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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