SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc6fb5d1fb84b493eccece79e3de2b7381011fd9f96c524e19effb70756250a' 
  AND token = 'QfVjdXHBAY49m7gp7UbXnreB4l/pBYqD3nS1sdii9Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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