SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd738306e8837d1918cba7562d56c48822a4a08039b4411250455a60ffeb7dde' 
  AND token = 'GunZSFVp/1fs51j/wnzpaf+L4B2kZHu0sG0biZ6Rh3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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