SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8a45c8bbd2372e7fd2562b1370f737c72b009e2faa19c7e31d8de84dd2a8b55' 
  AND token = '9QMJ+22ofTInkZZUNd1ikOGQcB2ruMZBK2I6mItUEG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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